Optical systems for photon management, that is the generation of tailored electromagnetic fields, constitute one of the keys for innovation through photonics. An important subfield of photon management deals with the transformation of an incident light field into a field of specified intensity distribution. In this paper we consider some basic aspects of the nature of systems for those light transformations. It turns out, that the transversal redistribution of energy (TRE) is of central concern to achieve systems with high transformation efficiency. Besides established techniques nanostructured optical elements (NOE) are demanded to implement transversal energy redistribution. That builds a bridge between the needs of photon management, optical engineering, and nanooptics.

The European Network of Excellence on Micro-Optics (NEMO) is a consortium of about 30 European institutes and companies which are working on micro-optics. The network is supported by the European Commission for a period of four years. One of its work packages is the Centre for Modelling and Design consisting of about 20 partners. In this work package a benchmark of the capabilities of commercial and internal software tools which are available among the partners will be made. The ten test systems which are used for the benchmarking range from seemingly simple things like calculating the intensity distribution in the focus of a microlens to complete systems like for example an optical interconnect system with microlenses, DOEs and a prism. The paper will present some of the benchmark systems. First results of the benchmarking itself cannot be presented in this proceeding because the benchmarking just ends at the end of August (after the deadline of this proceeding). But, hopefully first results can be presented during the talk.

In this contribution we present the accurate analysis and modeling of periodic optical structures that are finding wide application in photonics. The EM analysis is performed by two different 3D full-wave methods, the Transmission Line Matrix-Integral Equation (TLMIE) and the Generalized Transverse Resonance Diffraction (GTRD). TLMIE is a 3D full-wave hybrid technique in the time-domain which combines the advantages of the numerical TLM method and those of the analytical Green's functions representation for the free-space region, thus providing exact boundary conditions at optical frequencies. In GTRD the dyadic Green's function of a loaded box is used for the modeling of the layered structure, combined with Ohm's law formulation of the volume currents. By using the pre- and post-processing tools of TLMIE and GTRD methods, we investigate the dynamic of the EM field in and outside the structure and evaluate the frequency response of the laminated polarizer behaving as a negative uniaxial crystals. The calculated S-parameters are compared with measured data showing good agreement.

Depending on the specific application of a diffractive optical element (DOE), its polarization impact on the optical system must be taken into account. This may be necessary in imaging as well as in illumination optics, e. g., in miniaturized integrated optics or in high-resolution photolithographic projection systems. Sometimes, polarization effects are unwanted and therefore an exact characterization of their influences is necessary; in other cases a high polarization effect is the goal. It is well known how to calculate the point spread function (PSF) of a single diffractive micro-Fresnel lens. To do the same for a complete optical system with source, lenses, coatings, mirrors, gratings and diffractive elements, a 3D electrical field propagation along the geometric optical path is introduced into the ray-trace based optical systems design software in order to incorporate the entire electromagnetic polarization effects from the source to the image plane. Our software also considers the complex diffraction amplitudes including polarization effects from DOEs provided by rigorous electromagnetic methods. Together with a plane wave decomposition and with the local linear grating assumption, we are able to rigorously investigate the impact of e. g. polarization effects on the PSF of the whole optical system. Using this approach we analyze a hybrid diffractive-refractive microscope objective for mask inspection systems at 193 nm. Additionally we investigate focal properties of a sample diffractive blue laser disc pickup system.

In this paper we present a robust pseudo-random method for propagating an electromagnetic wavefront through an arbitrary optical system. The wavefront at an arbitrary plane is obtained by the discrete sampling of the wavefront in regular regions equally distributed on the entrance pupil and the appropriate modelling of the optical properties of the system. The discretization permits us to treat each region as a plane wave, so long as the area is small compared to the area of the pupil, therefore allowing us to apply the electromagnetic approximations of refraction and reflection during the transfer through an optical system. We can therefore account for amplitude and phase modulation of the wavefront due to the optical system, without making any assumptions about the shape of the optical elements. Furthermore, our numerical integration method on an arbitrary plane avoids singularities due to the classical analytical integrals, while still obtaining results comparable to rigorous electromagnetic theory. We have applied the method to simulating the propagation of both plane waves and spherical waves. The well known interference patterns of classical experiments such as Young's interference fringes or Newton's rings were reproduced accurately, with respect to results obtained applying analytical methods. We then successfully applied the method to analyze a Michelson interferometer set-up, demonstrating the robustness of the calculations. Since the propagation of the wavefront is possible with this method, in the future we plan to apply the method to simulating electrically large diffractive optical elements within a complex optical system, for which rigorous analytical methods may not be available, and other numerical methods generally require large computer resources.

During the last few years, the understanding of pupil plane manipulation capabilities to achieve an enhanced image formation process and its theoretical limitations becomes more and more important. Particularly the increased potential of computer calculations and digital signal detection makes it possible to simulate this kind of manipulations very fast and efficient. At the same time there is the opportunity to change the optical system such, that a digital reconstruction of the image gives a higher amount of information. An analysis of the optical transfer function as an important parameter of imaging quality with special interest in extended depth of focus is presented. The performance of different pupil plane masks is illustrated in comparison with standard optical systems. This means the basic features like depth of focus, resolution and contrast were derived and the limitations are shown. The mathematical principle of extended depth of focus with pupil manipulation is described and demonstrated with exemplary calculations. Furthermore, the relation between a given optical transfer function and the matching pupil function is shown. A robust and iterative algorithm is presented to calculate a pupil mask for a desired optical transfer function.

A general concept based on harmonic decomposition of pulses has been introduced to model ultra short pulse propagation through homogeneous and inhomogeneous dielectrics. This include propagation through free space, apertures and lens systems. This approach permits us to consider pulses of any arbitrary spatial and temporal characteristics. The pulse characteristics are found to be affected by angular and material dispersion. A computationally efficient method for the proper sampling of spectral phase has been introduced which requires only a minimum number of harmonic fields for the simulation. In the case of free space propagation, pulses maintains their shape but experience temporal and spectral shifts whose magnitudes depends on angular dispersion (diffraction angle). The pulse broadens, becomes asymmetric and chirped in dispersive media because of group velocity dispersion and higher order dispersion in the media. The pulse broadens due to radially varying group delay and group delay dispersion on propagation through focusing elements. The pulse energy at the focus is affected by the interplay of spherical and chromatic aberration by distributing the pulse energy over a large region on the axis.

Lens system design makes extensive use of optimization techniques to improve the performance of an optical system. We know that designing a lens system is a complex task currently done by experienced optical designers, using specialized optical design software tools. In order to contribute to this particular field, this paper presents a comparison between lens design done by optical designers and evolutionary algorithms lens based design. Evolutionary algorithms consist in population-based global search methods inspired by natural evolution. They are recognized to be particularly efficient for complex non-linear optimization problems. Given the non-linear nature of lens design as an optimization process, evolutionary algorithms are good candidates for automating this task. The evolutionary algorithms were applied to the monochromatic quartet that was presented to expert participants at the International Lens Design Conference in 1990 (a friendly competition). Comparative results demonstrate that the evolutionary approach is able to find solutions slightly better than those presented at the competition. Then a real-life imaging problem is tackled. Results show that an evolutionary algorithm is again able to discover lens systems comparable to design done after a reasonable effort by experts. This paper presents an analysis of this approach for automatic lens design from a real-life optical design point of view.

A variety of simulation tools, including optical design and analysis, have benefited by many years of evolution in software functionality and computing power, thus making the notion of virtual design environments a reality. To simulate the optical characteristics of a system, one needs to include optical performance, mechanical design and manufacturing aspects simultaneously. To date, no single software program offers a universal solution. One approach to achieve an integrated environment is to select tools that offer a high degree of interoperability. This allows the selection of the best tools for each aspect of the design working in concert to solve the problem. This paper discusses the issues of how to assemble a design environment and provides an example of a combination of tools for illumination design. We begin by offering a broad definition of interoperability from an optical analysis perspective. This definition includes aspects of file interchange formats, software communications protocols and customized applications. One example solution is proposed by combining SolidWorks¹ for computer-aided design (CAD), TracePro² for optical analysis and MATLAB³ as the mathematical engine for tolerance analysis. The resulting virtual tool will be applied to a lightpipe design task to illustrate how such a system can be used.

Specifics of non-imaging optical systems require special algorithms for automated optimization. We have implemented two methods into commercially available optical design software, which are robust and numerically effective. The first one is a modification of the edge-ray principle. In this case the optimization criterion should be expressed in geometrical terms (like, for example, collimation of an extended light source). This gives us the possibility to design not only CPClike collimators, but also rather complex refractive-reflective (RXI-like) devices. For the second (more general) case the optimization criterion is expressed in energetic terms. In this case stochastic behavior of the merit function due to Monte-Carlo ray-tracing procedure limits the applicability of standard optimization routines available in optical design software. We have realized a direct optimization algorithm, which does not calculate the derivatives of the merit function leading to reduced sensitivity with respect to local statistical deviations. The proposed algorithm is deterministic and does not suffer from redundant trials of random search. As a parametric description for the objects to be optimized we propose the use of piecewise Bezier splines. This allows relative strong shape bending but requires control for intersections. A "red-blue intersection reporting" algorithm is realized as a constraint for optimization.

In modern optical engineering the simulation of imaging and non-imaging optical systems on the basis of wave optics is of increasing importance. A simulation based on wave optics means on one hand to use everywhere in the optical system a wave-optical description of light. This allows the evaluation of more general merit functions for the description of the system quality which requires, for example, access to amplitude, phase, polarization, coherence information of light. On the other hand, including wave optics in optical simulations means to model the light propagation exact enough to describe wave-optical propagation effects. That means in general not to perform all simulations without physical approximations but to use light propagation models that work with sufficient physical precision within the optical system. The authors will discuss which needs follow for modern optical simulation software. This discussion includes a flexible handling of different models for simulation of light propagation, descriptions of different wave-optical light representations and considerations of numerical and physical simulation precision.

The main application of Monte Carlo methods in raytracing software lies in the field of scattering analysis. The basis for this simulation in raytracing software is the variation of the ray direction after refraction described by a Bidirectional Scattering Distribution Function (BSDF). In the simpliest case the scattering process is described by a BSDF which only depends on the scattering angle. We have extended this simple approach in different directions. One extension enables the simulation of different surface scattering effects. For example with a BSDF, which varies with the ray height on the surface, the local variation of the surface roughness due to fabrication effects can be simulated. Another extension allows the simulation of volume scattering. In this case the scattering properties of the material can be described by two functions: As before a scattering function determines the change in the ray direction due to local defects in the material. Additionally a function for the free path length is used e.g. to describe the density of local defects in the volume. The requirements and the limitations of the methods are shown and discussed. Several examples of typical applications are presented.

After having summarized the different methods in use to tolerance optical systems, with advantages and drawbacks, we present a new software, called TOLTRI, to post process the data's of tolerancing obtained with the TOR routine of CODE V and also introduce new features which are not possible in another way. This software accelerate the interpretation and discussions between the different disciplines involved, by presenting and sorting the results on separate EXCEL sheets and Matlab figures.

The history of lens design software is sadly littered with accounts of excellent programs which fell by the wayside for lack of support. Others evolved through various package formats to form the foundation of today's very successful commercial software. One example of this is the Imperial College lens design program developed throughout the 1960s, 1970s and 1980s by Charles Wynne, Michael Kidger, Prudence Wormell, and others. This program (best known as the Kidger Optics Ltd SIGMA) produced many excellent designs over the years. One reason was that the ray patterns and weighting factors for operands in the default merit function had been carefully honed through experience, to produce rapid convergence on the global optimum from a likely starting point. This paper describes a suite of optimisation raysets and weighted operands written in the C-like OSLO compiled macro language CCL, and modeled on the Imperial College tradition. It is available for free download from http://www.lambdares.com/techsupport/kb/index.phtml. Its prime function is to provide a fast, easily understood introduction to merit function construction for the beginner. One version is for use on OSLO EDU, the free version of OSLO, which is also available from the Lambda Research Corporation website. This paper demonstrates how OPIC can be used to locate, from a remote starting point, the global minimum of the "monochromatic quartet," the lens design problem from the SPIE 1990 International Lens Design Conference.

The use of a segmented merit functions in the optical design process is a good strategy to improve the optimization trajectories, however to reach good results it is necessary to change the segmentation of the merit function during the optimization. In this work we present a new application of the aplanatism condition, where it is used as a method to segment the merit function when extended objects are involved in the merit function definition. Our method begins with an equally distributed first sampling of the object to evaluate how far the sampled point is from the aplanatic condition. This initial value collection are used to obtain a second sampling of the object that provides the appropriate number of object field points that must be taken into account to use in the merit function. The use of the aplanatic condition to obtain dynamic merit function segmentation is especially important when large object fields are involved in the design process. We have tested the method using a wide field of view objective. The final objective configuration was obtained twice, one with a standard segmentation of the merit function (on axis, zonal point and full field) and two, with our method. The merit function, the optimization strategy, the variables and the initial system used are the same for both optimizations.

Because of the index change between water and air, dive masks with flat interfaces magnify by a factor of 1.34X, and the field of view (FOV) in water is restricted to about 60 degrees. In addition, the image suffers significant amounts of lateral color and distortion. For technical diving applications (e.g., underwater welding), these attributes reduce situational awareness, lead to poor hand-eye coordination and are highly undesirable. This paper describes the design issues and design solution of a unity magnification dive mask covering a full FOV of 140 degrees.

In this paper several techniques are described to perform the determination and correction of lens distortion in fringe projection systems for 3D object measurement. A new method to realise distortion determination for projection systems is introduced. It uses a plane surface and the projected fringe pattern as calibration tools and determines simultaneously the distortion of both projector and camera lens within an iterative procedure. The lens distortion calibration is performed in the state of the device "ready for measurement" which avoids errors by a later adjustment. A reduction of distortion errors up to 0.02 pixels in the projector chip and also in the camera chip is possible and leads to considerable improvements in the 3D measurements.

The effects of atmospheric differential refraction on astrophysical measurements are well known. In particular, as a ray of light passes through the atmosphere, its direction is altered by the effects of atmospheric refraction. The amount of this effect depends basically on the variation of the refractive index along the path of the ray. The real accuracy needed in the atmosphere model and in the calculation of the correction to be applied is of course, considerably worse, especially at large zenith angles. On the VLT Survey Telescope (VST) the use of an Atmospheric Dispersion Corrector (ADC) is foreseen at a wide zenith distance range. This paper describes the software design and implementation aspects regarding the analytical correction law discovered to correct the refraction effect during observations with VST.

Bi-directional Reflectance Distribution Function (BRDF) measurements that characterise the scattering properties of surfaces are extremely important to the design of optical instruments. Sophisticated codes require the characterisation of the scattering function of optically black and/or differently machined surfaces at several angle of incidence in a wide range of detector angles. These data can be used to develop processes to achieve desired BRDF patterns or to improve stray light suppression techniques. In this paper, we present the characteristics of an automatic, three dimensional, BRDF measurement set up that has been designed and developed at Galileo Avionica by the authors and the most significant experimental results of 3D BRDF data achieved on samples of aluminium alloys, gold and titanium, differently machined and/or black painted. The measurements have been taken at different illumination angles (from the normal incidence up to 45 degrees) at the wavelength of 650 nm. The wide variety of possible applications that can be explored through the proposed equipment, jointed to its flexibility, constitute a reference point for future investigations on the characterisation of the scattering properties of machined materials and paintings.

We have designed an ocular aberrometer based on the Hartmann-Shack (HS) type wavefront sensor for use in optometry clinics. The optical system has enhanced versatility compared with commercial aberrometers, yet it is compact and user-friendly. The system has the capability to sense both on-axis and off-axis aberrations in the eye within an unobstructed 20 degree field. This capability is essential to collect population data for off-axis aberrations. This data will be useful in designing future adaptive optics (AO) systems to improve image quality of eccentric retinal areas, in particular, for multi-conjugate AO systems. The ability of the examiner to control the accommodation demand is a unique feature of the design that commercial instruments are capable of only after modification. The pupil alignment channel is re-combined with the sensing channel in a parallel path and imaged on a single CCD. This makes the instrument more compact, less expensive, and it helps to synchronize the pupil center with the HS spot coordinate system. Another advantage of the optical design is telecentric re-imaging of the HS spots, increasing the robustness to small longitudinal alignment errors. The optical system has been optimized with a ray-tracing program and its prototype is being constructed. Design considerations together with a description of the optical components are presented. Difficulties and future work are outlined.

We report the in situ characterization of a semiconductor saturable absorber mirror (SESAM) in an operating Yb:KGW mode-locked laser. The technique may be described as a pump-probe experiment in which the intracavity beam acts as a pump beam, while the output of the same laser is used as a test beam for the SESAM reflectivity. At zero delay, the probe pulse overlaps in time with the subsequent intracavity pulse. The method is an alternative to standard pump-probe measurements, in situations where the intracavity parameters such as energy fluence onto the SESAM, pulse length and center wavelength can not be simultaneously achieved with available lasers.

Nowadays optical design for microscopes encloses besides the classical approach many new ideas like implementation of new optical elements, the consideration of physical effects or digital image processing. All these things play an important role during the development of microscopes and microscopic components at Carl Zeiss. In this paper we present examples of the classical approach starting with the imaging theory of Ernst Abbe as well as the non-classical approach ranging from microscopic objectives with diffractive optical elements over the implementation of the propagation theory of short-time laser pulses in optical design software to digital image restoration and phase measurement.

When we design lenses, we always wonder if any better design exists than the current design. If the current design could be proved to be the global minimum under given conditions, we could be fully confident on our design. In this paper I would like to show an example of such a proof. The design example is the "reversible lens", 1985 International Lens Design Conference lens design problem. This problem requests the aberration control at the lateral magnifications -1/2 and -2 simultaneously. From the nature of light, the perfect imaging at the 2 magnifications can not be realized. Some researchers have been interested in the problem to predict the performance limit quantitatively, and to find the real design that realizes this performance limit. In 1992 Forbes and Jones applied a global optimization to this problem and showed some solutions with different element numbers. In 1995 Forbes and Wallace predicted a performance limit by the method of the optimization of the Eikonal function. But this prediction was much better than the performance of the ever-found solutions. In this paper I investigated the prediction of Forbes and Wallace and modified their prediction. I also designed a real lens that reaches the predicted performance limit.

Triggered by the roadmap of the semiconductor industry, tremendous progress has been achieved in the development of Extreme Ultraviolet (EUV) sources and high-quality EUV optical coatings in recent years, opening up also new fields of applications apart from microlithography, such as metrology, high-resolution microscopy, or surface analysis. In all these research areas the quality and imaging properties of the employed optics play a crucial role. In this contribution we present a comparison of different optical setups capable of guiding and imaging EUV radiation, which were tested in combination with a miniaturized laser-produced plasma source with high pulse energy (~ 3.5 mJ @ 13.5 nm) and a plasma size of about 300 μm. First, a modified EUV Schwarzschild objective with a numerical aperture of 0.44 and a demagnification factor of 10 was developed within the research project "KOMPASS". After adaptation to the table-top EUV source, a focus with a diameter < 30 μm at energy densities of several mJ/cm² could be produced. The setup is currently being used for comparative investigations of the interaction of EUV radiation with different materials, as e.g. the color center formation in LiF crystals. An attempt to use the Schwarzschild objective in reverse geometry as a EUV microscope will be part of future work. Second, a Kirkpatrick-Baez arrangement was realized, using the reflections from two curved silicon wafers under grazing incidence (about 5°). The cylindrical curvature is obtained by bending the thin substrates, allowing for a continuous tuning to the desired radii. Due to an Au coating a high reflectivity (theoretically ~ 80 % per reflection) over a broad EUV spectral range can be achieved. For reduction of aberrations the optical systems were fine-adjusted with the help of a Hartmann-Shack wavefront sensor both in the visible and in the EUV spectral range. The imaging properties in the EUV range were determined and compared to ray tracing calculations performed with ZEMAX.

Finding multiple local minima in the merit function landscape of optical system optimization is a difficult task, especially for complex designs that have a large number of variables. We discuss here a method that enables a rapid generation of new local minima for optical systems of arbitrary complexity. We have recently shown that saddle points known in mathematics as Morse index 1 saddle points can be useful for global optical system optimization. In this work we show that by inserting a thin meniscus lens (or two mirror surfaces) into an optical design with N surfaces that is a local minimum, we obtain a system with N+2 surfaces that is a Morse index 1 saddle point. A simple method to compute the required meniscus curvatures will be discussed. Then, letting the optimization roll down on both sides of the saddle leads to two different local minima. Often, one of them has interesting special properties.

The multidimensional merit function space of complex optical systems contains a large number of local minima that are connected via links that contain saddle points. In this work, we illustrate a method to construct such saddle points with examples of deep UV objectives and extreme UV mirror systems for lithography. The central idea of our method is that, at certain positions in a system with N surfaces that is a local minimum, a thin meniscus lens or two mirror surfaces can be introduced to construct a system with N+2 surfaces that is a saddle point. When the optimization goes down on the two sides of the saddle point, two minima are obtained. We show that often one of these two minima can be reached from several other saddle points constructed in the same way. The practical advantage of saddle-point construction is that we can produce new designs from the existing ones in a simple, efficient and systematic manner.

Weight optimization here stands for optic design, i.e. creation of a new optical system, on the assumption that weight should be a minimum! This will be done only by means of traditional design methods, that is excluding the use of aspherical surfaces, plastic materials, mirrors, diffractive or similar elements! This demand for lowest possible weight is important with systems, that must be transported for example into space, as well as with handheld systems, for instance binoculars, riflescopes, but also with photographic lenses. Up to now, no theory exists which describes how this problem can be solved. Here, the essay begins with the fundamentals, after that the basic facts related to the weight of a lens are discussed, as well as references made to publications. At the end, two design examples are given, the first being a binocular. The second example shows, that even in hopeless cases sometimes a solution can be found.

To fulfil the requirements of today's high performance cine lenses aspheres are an indispensable part of lens design. Among making them manageable in shape and size, tolerancing aspheres is an essential part of the development process. The traditional method of tolerancing individual aspherical coefficients results in unemployable theoretical figures only. In order to obtain viable parameters that can easily be dealt with in a production line, more enhanced techniques are required. In this presentation, a method of simulating characteristic manufacturing errors and deducing surface deviation and slope error tolerances will be shown.

New projection concepts based on OLED (organic light-emitting diode)-microdisplays will be presented. Up to now mostly all projection systems are based on reflective and/or transmissive microdisplays like digital micromirror devices (DMDs), nematic liquid crystals displays (LCDs) or liquid crystal on silicon displays (LCOS). But the size of necessary light source and illumination optics is a strong limitation for the miniaturization of the projection system itself or for system integration. Here we propose to use a high-brightness OLED-microdisplay as active element for image or pattern generation, giving the possibility to realize compact projection or imaging units. Optical parameters of the microdisplays are determined to get input data for optical system design. Based on these experimental results specially adapted optical systems are designed. First prototypes and realized projection systems for applications in optical 3Dshape detection are presented.

Recently, the development of high NA lenses for immersion lithography turned from dioptric concepts to catadioptric design forms. The introduction of mirrors involves the new challenge to deal with the inevitable obscuration of either field or pupil. We review the strategies used in this regard for microlithography, while focussing on the two most favored ones, folded and inline concepts. Although the vignetting situation is more complicated for inline systems, we report progress in this field of optical design yielding similar system performance for inline and folded designs. Since inline optical systems are much easier to realize, these are the concept of choice.

A wide-angle catadioptric lens with the rectilinear projection scheme has been designed and fabricated using an ultraprecision contouring machine. The completed imaging system has a wide field of view of 160°.

Last advances in optical design and manufacturing have helped to enlarge possibilities for optical solutions in any field that used optics elements. However, the useful solution is not always the best theoretical achievable one. Now, to find the right solution, the restrictions usually do not come from theoretical limits of optics, but from the feasibility of its practical implementations. This paper analyzes a set of important figures to be considered in the design of concentration optical system for photovoltaic solar energy applications. To illustrate it, the ISOFOTON optical concentration option will be presented. It is based in an innovative design methods of non-imaging optics and it is called TIR-R^[1]:a two stage concentrator with a primary lens, working mainly by total internal reflection, plus a secondary lens, working by refraction.

The control of optical distortion is useful for the design of a variety of optical system. The most popular is the F-theta lens used in laser scanning system to produce a constant scan velocity across the image plane. Many authors have designed during the last 20 years distortion control corrector. Today, many challenging digital imaging system can use distortion the enhanced their imaging capability. A well know example is a reversed telephoto type, if the barrel distortion is increased instead of being corrected; the result is a so-called Fish-eye lens. However, if we control the barrel distortion instead of only increasing it, the resulting system can have enhanced imaging capability. This paper will present some lens design and real system examples that clearly demonstrate how the distortion control can improve the system performances such as resolution. We present innovative optical system which increases the resolution in the field of view of interest to meet the needs of specific applications. One critical issue when we designed using distortion is the optimization management. Like most challenging lens design, the automatic optimization is less reliable. Proper management keeps the lens design within the correct range, which is critical for optimal performance (size, cost, manufacturability). Many lens design presented tailor a custom merit function and approach.

Stationary Fourier transform spectrometry is a well-known concept to build reliable field or embedded spectroradiometers, especially for the mid- and far- infrared. However, the quality of the interference pattern imaged on the focal plane array is crucial to obtain a good spectrum by Fourier transform. We describe here an accurate modeling of the interferometer behavior that takes into account the instrument aberrations and field of view in order to quantitatively predict, at each wavelength and for a spatially extended uniform incoherent source, the real interferogram defects, namely, fringe distortion, fringe blurring and illumination non-uniformity. To investigate these effects, we first derive the properties of the elementary interferograms built by each source point. For this purpose, we use ray-tracing to extract optical path and vignetting information with the help of a commercial optical design software package, and we reconstruct from them the two wavefronts that hit the detector using general numerical methods with the help of standard computing tools. The whole interferogram being formed by the incoherent superposition of all elementary interferograms, we next, compute the relevant quantities by appropriate numerical quadratures. We illustrate this method with two potential layouts of a Fourier transform spectrometer that we are currently designing for accurate radiometric measurements in the 2.9μm-9.6μm range with a spectral resolution better than 8cm^-1 on a 4.5°x0.6° field of view.

The axicon is an optical element which creates a narrow focal line along the optical axis, unlike the single focal point produced by a lens. The long and precisely defined axicon focal line is used e.g. in alignment, or to extend the depth of focus of existing methods such as optical coherence tomography or light sectioning. Axicons are generally manufactured as refractive cones or diffractive circular gratings. They are also made as lens systems or doublet lenses, which are easier to produce. We present a design in the form of a reflective-refractive single-element device with annular aperture. This very compact system has only two surfaces, which can be spherical or aspheric depending on the quality required of the focal line. Both surfaces have reflective coatings at specific zones, providing an annular beam suitable for generating extended focal lines. One draw-back of a normal axicon is its sensitivity to the angle of illumination. Even for relatively small angles, astigmatism will broaden the focus and give it an asteroid shape. For our design, with spherical surfaces concentric about the center of the entrance pupil, the focal line remains unchanged in off-axis illumination.

Dioptric systems are usually the first choice for the design of an optical system, e.g. a projection lens or a microscope. But in some cases refractive designs suffer from serious drawbacks like chromatic aberration or material problems (cost, quality, absorption, birefringence, etc.). In such cases reflective systems are an attractive alternative. Reflective systems can be subdivided into two classes: on one hand there are systems with central pupil obscuration, e.g. reflective microscopes or telescopes in astronomy, which have a high aperture but only a small field size, on the other hand there are unobscured systems, e.g. reflective relay systems or EUV projection lenses, which have a large field but only small aperture. By the combination of an unobscured and an obscured mirror system one obtains systems with large field and high numerical aperture. We present new designs, which prove this design principle.

Depth of focus can be enhanced with cubic phaseplates located at the exit pupil of an optical system without significant loss of resolution. The enhancement factor is proportional to the strength of the phaseplate. The digital image is inversely filtered. The stronger the phaseplate is the stronger the inverse filter function must be. This causes increasing noise for high spatial frequencies in the restored image. Therefore, an optimum strength of the cubic phaseplate has to be chosen for the respective situation. A variable phaseplate system has been realized and tested. The performance of the setup has been experimentally studied. Applications and practical aspects are discussed in particular regarding barcode readers.

In a conventional particle tracking system, the depth of field is usually very small because of the use of high power imaging lens. The tracking accuracy may also be affected by the smearing of spot image, caused by focal shift. Increasing the focal depth and keeping uniform spot size in the focal region is highly desirable for a high accurate tracking system. In this report, we study the design of phase apdodizer that could be used to increase the focal depth of a tracking lens. The design is based on the requirements by highly accurate tracking that the point-spread function (PSF) of the lens keep an even and concentrated energy distribution when the lens is defocused. To achieve this purpose, a pure phase-shifting apodizer is introduced on the pupil plane of the lens. The function of the apodizer is to control the energy distribution of the 3D diffraction pattern near the focal region and make the effective spot size uniform or minimum variation along optical axis. The pattern of the 3D PSF of the lens with the apodizer shapes closed to a cylinder. New method used to search and optimize the design of the phase apodizer that meet the requirements of a particle tracking system will be studied. Theoretical analysis and numerical simulation are given in support of the method.

Numerous optical systems, such as telescopes, adaptive optics systems, and aberrometers, are equipped with wavefront sensors, which often use sampling devices measuring the slope of the wavefront at discrete points across the pupil (e.g. Shack-Hartmann sensors). The accuracy of the sampled output signal is always affected by the fabrication and alignment tolerances of the wavefront sensing optical system. Typically, it is a requirement to express the measurement error in terms of input wavefront, so the optical ray intercept error has to be converted into wavefront measurement error. This conversion cannot be obtained directly from a conventional tolerance analysis because of the wavefront breaking by the sampling device. The tolerancing method proposed in this paper solves the problem of converting conventional merit function degradation into input wavefront measurement error. The proposed method consists of two parts. First, a Monte Carlo tolerance analysis based on a specific merit function is performed, and a 90% border system is selected. Then, an optimization is applied to the 90% border system, by varying a "dummy" phase surface introduced at the entrance pupil of the system. A concrete example is presented.

For gaining a deeper understanding of the diffraction processes that take place in deep dielectric transmission gratings, a phenomenological explanation has been developed on the basis of a modal field, which propagates vertically through the grating region. The excitation of these modes by the incident wave, their propagation constants and how they couple to the diffraction orders determines the diffraction efficiency of the transmitted orders. The explicit modal analysis discloses the description of the highly efficient diffraction for polarized or unpolarized light by a very simple interference mechanism, which will be the subject of this paper.

Projection lenses for high resolution lithography have high NA and work at small wavelengths. In the wavelength regime of VUV (e.g. 193nm), there is a very limited number of optical glasses available, namely fused silica and calcium fluoride. The latter is very expensive and used only sparely, leading to limited possibilities for chromatic correction. In addition to catadioptric approaches, another way to deal with chromatic aberrations is the use of diffractive optical elements (DOEs). They have negative dispersion coupled with positive power and they do not contribute to the Petzval sum. Moreover, it is easy to integrate an aspherical functionality into the structure of the DOE. Usually a DOE is placed close to the aperture stop to correct axial color. The stop of a lithographic projection lens often is located at the largest diameter, causing some serious fabrication difficulties for the DOE. For this reason a class of lenses with intermediate image is of interest. Here, the accessible conjugate of the aperture stop enhances the possibilities to arrange the stop and the DOE. This allows a convenient tradeoff between fabrication challenges and aberration correcting properties. We present different lens designs that take advantage of the named properties of DOEs at high numerical aperture.

Micro and nano optics enable the control of light for producing intensity distributions with given profiles, propagation properties and polarization states. The higher the requirements on the optical function, the more complicated will be its realizing with a single element surface or a single element class. Combinations of refractive and diffractive, both diffractive or sub-wavelength structures with each other give the ability to link the advantages of different element classes or different element functions for realizing the optical functionality. In the paper we discuss two different examples of combinations for DUV applications. In detail we present a diffractive - diffractive beam homogenizer with NA of 0.3 that show no zero order. A binary phase grating for polarization control combined with a beam shaping element will be presented. The polarized order of this grating shows an efficiency of about 90% with a degree of polarization better than 90%. Wave optical and rigorous design strategies and simulations as well as the optical measurements will be discussed for the given examples.

Diffuser technology is known in diffractive optics for several decades and was mainly used together with coherent monochromatic light sources. In the last years diffusers play a more important role for illumination and homogenization task of partial coherent light sources, for example, Excimer lasers and LED's. In difference to illumination systems using lenses and micro lens arrays diffusers can be used to freely redistribute the intensity of the light source with a high homogeneity. Using diffuser technology for partial coherent illuminations needs an understanding of the characteristics of the light sources as coherence, wavelength bandwidth, divergence, radiation characteristic/intensity distribution. Since these characteristics are different for coherent and partial coherent light sources, these must be taken into account during the design of diffuser. This leads to new design concepts and surface structures. The authors will explain concepts of diffuser design for LED's and Excimer lasers and will show practical results.

To study the quantitative impact of diffractive optical elements on lens design and glass selection, a Zeiss Tessar lens (f/6) with and without a diffractive optical element is optimized with respect to the wavefront performance by a Zemax(R) Hammer routine. Optimization includes the selection of glasses as well as the geometry of the optical elements. In a first run, these are all refractive elements. In a second run, one refractive element is replaced with one diffractive surface. In a third run, the diffractive surface is introduced as an additional feature. It is found that one refractive element can be replaced with a diffractive surface at a moderate loss of lens performance. This holds, however, only for an optimized glass selection, which is found to be particularly important. In the case of four refractive elements plus diffractive surface, an according result is obtained. The diffractive surface will improve the overall system performance if and only if the glass selection is appropriate.

Established phase contrast methods in microscopy use the phase-shifted zeroth order Fourier component of an image-carrying light wave as a reference wave for interferometric superposition with the remaining part of the image wave. Our method consists of a spatial Fourier filtering of the image wave with a spiral phase element which leads to an edge enhancement of both amplitude and phase objects. The spiral phase element is realized by displaying a high resolution phase hologram on a computer-controlled reflective spatial light modulator. The edge enhancement is isotropic which means that all edges are highlighted simultaneously. Controlling the phase of the central area of the hologram leads to an interference image that has a 3-dimensional appearance of the object. In order to allow for white light imaging, the dispersion is compensated by a special double-diffraction setup.

A homogeneous illumination of a microscope requires a homogeneous intensity distribution in the field plane and in the pupil plane. An inhomogeneity in the pupil gives rise to a distortion in the image. This distortion is more clearly seen in defocused image planes and is commonly misinterpreted as classical aberration. An inhomogeneous intensity distribution in the field plane causes for example a line thickness variation of an imaged structure. In classical microscopy which operates with classical light sources, for example spiral-wound filaments, the task of designing a homogenised illumination can be solved using geometrical optics. Using instead of an incoherent a partial coherent light source may lead to interferences in the pupil and in the field plane which represent the major problem of such illumination systems. We present simulated results concerning the propagation of partial coherent light. The lateral and temporal coherence of a multimode laser was determined experimentally. With these results simulations were done using partial coherent beams. The considered optical components include lenslet arrays and diffractive optical elements.

A 21x Schwarzschild microscope lens for the EUV spectral range with a numerical aperture of 0.2 was designed and fabricated. The mechanical design of the lens had to comply with high requirements on surface figure amounting to 0.4 nm r.m.s. error for both mirrors. An optimized mirror mount was developed which is based on solid state hinges. In particular, gravity load, intrinsic stresses of the multilayer reflective coating as well as mounting forces and possibilities for mirror adjustment had to be considered. To provide a completely hydro-carbon free design the hinges were connected to the mirror by flux-less soldering.

In a number of applications the high precision microscopes are indispensable and rather complex instruments, which have afocal optical systems. The magnification of afocal optical systems is independent of the object distance. Therefore we can form a real image with a constant height of an object from a comparatively big object distance range [1]. Our aim is to develop an afocal optical system with a relatively big numerical aperture that facilitates the description of the vectorial calculation of electromagnetic field propagation from the object to the image [2]. The preconditions of these vectorial calculations will be achieved by a complex rear and a single front elements special afocal optical system, of which the following are strictly true: The object is in the front focal plane of the front element, the image is in the rear focal plane of the rear element, the aperture stop is in the rear focal plane of the front element and in the front focal plane of the rear element on the adjacent coincidental focal planes. Consequently, the raytracing is telecentrical in both the object and image space. The presentation shows the design of the afocal optical system that satisfies the above conditions and specifications.

The Space Infrared Telescope for Cosmology and Astrophysics (SPICA) mission is the third Japanese astronomical infrared satellite project of a 3.5m cooled telescope optimized for mid- to far-infrared observations, following the Infrared Telescope in Space (IRTS) and the ASTRO-F missions. It will employ mechanical coolers and an efficient radiative cooling system, which allow us to have a cooled (4.5K) telescope of the aperture much larger than previous missions in space. The SPICA will attack a number of key problems in present-day astrophysics, ranging from the origin of the universe to the formation of planetary systems, owing to its high spatial resolution and unprecedented sensitivity in the mid- to far-infrared. The large aperture size for cryogenically use is, however, a great challenge and demands substantial technology developments for the telescope system. We adopt monolithic mirror design in the baseline model because of the technical feasibility and reliability. We set the optical performance requirement as being diffraction limited at 5μm at the operating temperature of 4.5K. The total weight attributed to the telescope system is 700kg, which requires a very light 3.5m primary mirror together with the mirror support structure. At present we are working on two candidate materials for the SPICA telescope: silicon carbide (SiC) and carbon-fiber reinforced silicon carbide (C/SiC). This presentation gives a general overview of the SPICA mission and reports the current design and status of the SPICA telescope system, including recent progress of the development of C/SiC mirrors.

Monitoring of the oceans from satellite requires frequent updates - preferably with global coverage in one day, excluding effects of cloud. This demands optics covering swath widths up to about 3000km, within which spatial resolution in the order 250m or less is desirable for observation of coastal zones. Wide field angles, typically around 90°, are needed for optical systems operating from altitudes that are typical for polar orbiting satellites. At least 15 resolved spectral bands are needed in the visible and near-IR regions, requiring wide-field imaging spectrometers or designs using multiple filters. Other constraints on optical design include requirements for radiometric calibration, precise spatial registration of spectral bands, good control on stray light, and insensitivity to polarisation. The paper describes two design forms in which a single optical channel provides the complete wide-angle field, with appropriate allowances for calibration etc. In the first design, a wide angle telescope is followed by a spectrometer and an area-array detector. The spectrometer uses refractive dispersion for stray light control, and gives good spatial and spectral registration. In the second design, spectral resolution is provided by a set of filters with linear array detectors. In-field separation of detectors is used to avoid a need for dichroic beam splitters or dispersive optics; spatial registration in this case demands exceptional distortion correction, that takes account of Earth curvature. Both designs provide an external entrance pupil for location of calibration hardware.

The Ozone Monitoring Instrument (OMI) was launched on 15 July 2004 on NASA's EOS AURA satellite. The OMI instrument is an ultraviolet-visible imaging spectrograph that uses two-dimensional CCD detectors to register both the spectrum and the swath perpendicular to the flight direction with a 115 degrees wide swath, which enables global daily ground coverage with high spatial resolution. This paper presents a number of in-flight radiometric and spectral instrument performance and calibration results.

For the increasing market of low-cost multispectral pushbroom scanners for spaceborne Earth remote sensing the Jena-Optronik GmbH have developed the JSS product line. They are typically operated on micro-satellites with strong resources constraints. This leads to instrument designs optimised with respect to minimum size and mass, power consumption, and cost. From various customer requirements, Jena-Optronik has derived the JSS product line of low-cost optical spaceborne scanners in the visible wavelength range. Three-mirror anastigmat (TMA) telescope designs have become a widespread design solution for fields of view from 2 to 12 deg. The design solution chosen by Jena-Optronik is based on all-aluminium telescopes. Novel ultra-precision milling and polishing techniques now give the opportunity to achieve the necessary optical surface quality for applications in the visible range. The TMA telescope optics design of the JSS-56 imager will be accommodated onboard the RapidEye spacecraft. The JSS-56 TMA with a F-number of 4.3 realised a swath width of 78km with a Ground pixel resolution of 6.5m × 6.5m. The aluminium mirrors are Ni coated to achieve a suitable surface polish quality. This paper discusses typical requirements for the thermal design the bimetallic effects of the mirrors. To achieve a nearly diffracted limited imaging the typical surface irregularities due to the turning process have to be addressed in the ray tracing models. Analysis and integration of real mirror data in the ZEMAX design software are demonstrated here and compared with build-in standard tolerance concepts.

This paper presents an analysis of the requirements for instruments for meteorological applications, presents different implementation options with their prime benefits and drawbacks and discusses the optimization space. The different scanner options with their influence on the architecture of the optical system and the focal plane assembly are addressed. This leads to different candidate implementations. For those the optimization space is described leading to a preferred solution in form of a rotating reflective optics, an in-field spectral separation and a matrix based focal plane assembly. The main advantages of such a system are its flexibility with respect to the possible number of spectral channels, the possible radiometric resolution, and the variability of the geometrical resolution. It is shown that results of a first design iteration demonstrate the feasibility of the chosen approach.

This paper describes the optical design criteria and expected image quality of the High Resolution Imaging Channel (HRIC), which is part of the Spectrometers and Imagers for Mercury Planetary Orbiter (MPO) BepiColombo Integrated Observatory SYStem (SIMBIO-SYS) suite, for imaging and spectroscopic investigation of Mercury. SIMBIO-SYS has been selected by ESA as part of the scientific payload of the ESA BepiColombo mission to Mercury. HRIC has the main objective of characterising Mercury surface features with a very high spatial resolution in the visible. The optical design has been optimised to achieve the stringent scientific requirement of 5 m ground pixel size at 400 km from the planet surface. The adopted catadioptric optical configuration provides a resolution of 2.5"/pixel for a pixel size of 10 micron. The focal ratio is F#8 in order to be diffraction limited at 400 nm and to optimise radiometric flux and overall mechanical dimensions. The optical design solution includes two hyperbolic mirrors optimized with a dioptric camera, in order to correct the field of view of 1.47°, covered by a detector of 2k x 2k pixels. The mixed (reflective + refractive) solution guarantees a good balance of achieved optical performances and optimisation of resources (mainly volume and mass). The adopted configuration corrects and transmits well over the whole band of observation (400 - 900 nm).

The Heliospheric Imager (HI) is part of the SECCHI suite of instruments on-board the two STEREO spacecrafts to be launched in 2006. Located on two different orbits, the two HI instruments will provide stereographic images of solar coronal plasma and coronal mass ejections (CME) over a wide field of view (~90°), ranging from 13 to 330 solar radii (R₀). These observations complete the 15 R₀ field of view of the solar corona obtained with the other SECCHI instruments (2 coronagraphs and an EUV imager). The HI instrument is a combination of 2 refractive optical systems with 2 different multi-vanes baffle system. The key challenge of the instrument design is the rejection of the solar disk light, with total straylight attenuation of the order of 10^-13 to 10^-15. The optics and baffles have been specifically designed to reach the required rejection. This paper presents the SECCHI/HI opto-mechanical design, with the achieved performances. A test program has been run on one flight unit, including vacuum straylight verification test, thermo-optical performance test and co-alignment test. The results are presented and compared with the initial specifications.

Since several years, EADS-Astrium has developed, in partnership with BOOSTEC, Silicon Carbide (Sic) structural pieces for space telescope applications. This technology has appeared adequate not only for optical elements (mirrors) but also for the complete Telescope structures, thanks to high stiffness, low coefficient of thermal expansion and high thermal conductivity of Sic. At the time being, two space Sic telescopes are operational in observation and scientific missions. Two other monolithic Sic telescopes, among the largest ever built, are in manufacturing progress. The latest innovations in Sic technology have been implemented in the ALADIN Telescope for the AEOLUS mission (LIDAR dedicated to wind speed measurement).

We have developed a star sensor as an experimental device onboard the SERVIS-1 satellite launched in October 2003. The in-orbit data have verified its fundamental performance. One of the advantages of our star sensor is that the baffle has a small length of 120 mm instead of 182 mm in the conventional two-stage baffle design. The key concepts for light shielding are total internal reflection phenomena inside a nearly half sphere (NHS) lens and scattering light control by gloss black paint. However, undesirable background noise by the sun outside of the field of view (FOV) was observed in the corner of the FOV in the orbital experiment. Ray trace simulations revealed that slight scattering light on the specular baffle wall entered the NHS lens and reached the corner of the image sensor through the multi-reflection path inside the lens. It was found that the stray light path can be shielded effectively if the diameter of the aperture under the NHS lens was reduced. We redesigned the baffle and evaluated the light shielding ability with our sun interference test facility on the ground, and confirmed that the stray light was reduced below the acceptable level. As a result, the light shielding technique which we have proposed was proved to be effective for a small-size baffle. The redesigned star sensor is planned to be installed as a main attitude sensor for the SERVIS-2 satellite scheduled to be launched in February 2008.

Hard X-ray telescope by means of optics is one of the key technologies for future X-ray observatory programs. Introducing a telescope to hard X-ray region above 10 keV will improve sensitivity by one or two orders of magnitude. The principle of hard X-ray telescope is a depth-graded multilayer (supermirror) and high throughput, nested thin-foil grazing incidence optics. We have successfully developed a hard X-ray telescope sensitive up to 50 keV for balloon program InFOCuS. Effective area of 50 cm2 at 30 keV and image quality of 2.5 arcmin (HPD) were obtained from ground-based measurement and were also confirmed by in-flight calibration. Recent development achieved an improvement of image quality roughly by a factor of two. Japan's future X-ray satellite program NeXT has been proposed based on our technology.

The performances of optical and radio frequency communication systems are compared for long distance applications, e.g. deep space communications, where the signal-to-noise ratio is crucial. We compare an optical communication system operating at 0.8 μm using intensity modulation and direct detection with an avalanche photodiode, an optical communication system operating at 1.5 μm using on-off keying and an optical preamplifier, and a radio frequency communication system operating in the X-band. Assuming typical system parameters for the link budget analysis, we find that for distances between the transmitting and receiving antennas (R) of 10⁶ km the signal-to-noise ratios for the optical systems are proportional to R^-4, and that for the radio frequency system is proportional to R^-2. For distances beyond 10⁷ km, the maximum data rate achievable with the radio frequency system is higher than that with the optical systems. For distances corresponding to low earth orbit links as well as for geostationary earth orbit links, an optical system with optical preamplification is preferable when the data rate is higher than several Gbit/s.

The near-infrared spectrograph (NIRSpec) is part of the James Webb Space Telescope (JWST) science mission: NIRSpec is a spectrograph that works in the near infrared spectral region (0.6micron - 5.0micron) and allows the observation of spectral features of the incident star light with different spectral resolution (R=100, R=1000, R=3000). It is designed for spectroscopy of more than 100 objects simultaneously. The optical design of the NIRSpec instrument is characterized by a straight optical system layout: It constitutes of a set of optical modules of similar optical design type with high performance and low module tolerances. The NIRSpec instrument development is a cooperation of the European Space Agency and EADS Astrium Germany GmbH as prime contractor for instrument development, design, and manufacturing.

PLANCK is the space mission of the European Space Agency devoted to measure of the anisotropies of the cosmic microwave background (CMB), the relic radiation left by the big bang. The satellite will be launched in 2007 and it will carry state-of-the-art of microwave radiometers and bolometers arranged in two instruments, respectively the Low Frequency Instrument and the High Frequency Instrument, both coupled with a 1.5 m telescope and working in nine frequency channels between 30 and 857 GHz. From the second Lagrangian point of the Sun-Earth system, the instruments will produce a survey that will cover the whole sky with unprecedented combination of sensitivity, angular resolution, and frequency coverage, and they will likely lead us to extract all the cosmological information encoded in the CMB temperature anisotropies. The development strategy of PLANCK and the two instruments has been to set up a mission that inherently minimizes the systematic effects. The optics, composed by an optimised telescope-feed array assembly, introduce unwanted systematic effects in the measurements like the so called external straylight due to the sidelobe pick-up. A trade-off between angular resolution and external straylight has been carried out for LFI in order to reach the best optical performances preventing the Galactic contamination. The main product of the study has been the definition of the internal geometry of the flight model of the LFI feed horns and the characterization of the overall optical response of the instrument. Thermal emission from all components of the spacecraft produces the so called internal straylight, that has been evaluated and controlled in the design phase. In this paper we present the study carried out on the minimization of straylight contamination in PLANCK LFI.

In this paper, the design, manufacturing and testing of the optical subassembly specifically tailored for the acousto-optical Wide Band Spectrometer (WBS), subsystem of HIFI (Heterodyne Instrument for Herschel), is presented. The WBS optical sub assembly consists of a laser source module with two collimated lasers and a prism beamsplitter, and imaging optic modules. The light source is a near-infrared laserdiode operating at 785 nm. The outgoing beam from the collimating unit is elliptical with 8 mm width and splitted by a prism device into four beams. The quadruplets are focussed in the vertical direction by means of a cylindrical element thus achieving a four "sticks" like focussed pattern in an intermediate focus where the acoustic channels of a Bragg cell are positioned. A combination of scanoptic and cylindrical lens is used to image the deflected light on a four line linear CCD. The laser source unit has been designed to operate under paraxial working conditions. Despite the conceptually simple optical configuration, the system has represented a technological challenge, being of the order of few micrometres the integration scale for the optics and for the tight tolerance set requested in terms of degree of collimation and for the alignment precisions and stabilities over a wide range of temperatures and other environmental conditions.

This paper presents the design and key technologies of the Transmit-Receive Optics (TRO) for the Aladin lidar instrument. The TRO as the central optical interface on the Aladin instrument leading the optical signals from the laser source to the emitting/receiving telescope, and vice versa, the received back scattered signals from the telescope to the spectrometers for Doppler shift evaluation. Additionally, the TRO contains a calibration branch bypassing the telescope and aims at levelling out the received signals in terms of wavelength and signal height changes due to wavelength and intensity variations of the laser. The opto-mechanical concept of the TRO consists of afocal optical groups, which are connected by parallel beams. Extreme requirements have been defined for the TRO on the end-to-end transmission (>=73 %) with an associated effective bandwidth of less than 1 nm over the 200 - 1100 nm spectral range. The achieved solution is presented in this paper. A further feature of the TRO is the use of two so-called aberration generators on the emitting and calibration branch, with which an artificial astigmatism can be realised for eye safety reasons. Its effect on astigmatism is presented. This article also addresses the effort on stray light suppression, which is of extreme importance for the TRO. Special ion plated (IP) optical coatings have been used with superior performance for the TRO, particulary on laser energy resistance and air/vacuum stability. The development of special mounting technologies of optical elements to meet the stringent WFE, stability, and stray light requirements for the TRO are described. Key words : Aeolus Satellite, ALADIN instrument, Lidar, optical design, UV optics manufacturing technologies

This paper shows criteria and strategy followed for the optics design of VST telescope, and foreseen image quality. The optics design has been optimized in order to achieve the high required image quality on the base of main scientific requirements, mechanics constraints coming from the wide CCD mosaic camera and dimensional requirements. Manufacturing reliability integrated operational efficiency, and costs optimization criteria have been also taken into account. The VST optics has been designed in order to have a 2.61 m Alt.az telescope operating from U to I bands with an excellent image quality (80% of Encircled Energy enclosed in less than two pixels) on a wide field of view (1° x 1°). The telescope will have a very high resolution (0.21"/pixel) with a pixel size of 15 μm;. The peculiarity of VST optics design is that telescope configuration is not a pure Ritchey - Chretien, but it is integrated with two different refracting correctors in order to minimize residual field aberrations. One corrector is optimized for observations at small zenith angles (U-I bands), while the other one includes an ADC providing high quality images until zenith angles of 50° (B-I bands). This corrector is a very useful and innovative integrated facility. The optics is being manufactured from Zeiss/LZOS. The telescope is going to be mounted in Napoli before shipment to Chile where it will be installed near the giants VLT units and will be a dedicated wide field imaging facility operating in narrow and wide visible bands

This paper concerns optomechanics tolerances specifications for VST telescope. It shows the strategy of tolerances definition for optomechanical systems. These prescriptions are the baseline for development and tests of VST telescope optomechanic components. The telescope is provided with an active optics control system, so some tolerances may be relaxed, respect to passive systems designs since they can be actively compensated. Gravitational and thermal deformations have been also considered. The design error budget strategy is described. Manufacturing, mounting and alignment tolerances have been evaluated within the whole telescope image quality error budget, in terms of rms spot radius. Since the telescope is seeing limited, effects of atmospheric seeing have also been considered in the error budget in terms of CIR. Do to its large field of view (1 degree square), the VST optical design (optomechanics tolerances included) is the first source of error if compared to a classical telescope design that has a small field of view. The overall optical quality depends also on telescope configuration (ADC and one-lens corrector or two-lens corrector configuration) and on observational zenith angle (0÷50°).

The capability to perform Phased-Reference Imaging and Narrow-Angle Astrometry with the VLTI will be given by the PRIMA instrument, which is based on the simultaneous observation of two celestial objects separated by 2 to 60 arcsec. PRIMA facility will allow VLTI instruments like MIDI and AMBER to observe objects with magnitude fainter than in single field mode. PRIMA astrometric camera will allow to measure relative angular positions of stars with 10 uas accuracy. This paper reviews the concept and the implementation of the Fringe Sensor Unit, the PRIMA fringe sensor/astrometric instrument, which is currently under integration/test at Alenia Spazio.

This paper is about VST active optics system design, specifications and status. The VST is a modified Ritchey-Chretien wide field Alt-Az telescope with a corrector camera (1 square degree field of view), so when all optical components are correctly aligned, only residual aberrations in whole field are present. The major amounts of these aberrations can be introduced by gravitational and thermo opto-mechanical deformations and mirror misalignments. For these reasons active control of the primary mirror shape and secondary mirror position are required to lessen optical aberrations. The aim of active optics is to correct all optical telescope errors in order to make them small compared with external seeing. The VST is essentially compensated for static or slow frequency deformations and misalignments with a band pass from dc to 1/30 Hz, since the corresponding integration time is sufficient to integrate out the external seeing, giving a round image corresponding to the integrated external seeing quality. VST decentering, coma and defocus are corrected by mean of a secondary mirror position control system (a two-stage hexapode system) and spherical, astigmatism, quad-astigmatism and tri-coma are corrected by mean of M1 mirror shape deformation (axial and radial support system). For optical aberrations and guiding measurement an optical sensing arm has been designed.

The Launch Telescope Assembly (LTA) consists of a 50 cm class beam expander (angular magnification 12.5x) and it is an essential subsystem of Laser Guide Star Facility (LGSF), which provides an artificial reference star for adaptive compensation of atmospheric turbulence for one of the VLT (Very Large Telescope) 8-meters telescopes of ESO (European Southern Observatory). LTA is an afocal system, with parabolic primary and secondary mirrors, a flat 45° tertiary mirror and an exit window. It is fed with collimated Sodium laser beam, expanding and directing it along the line of sight of the 8-m telescope. Resonance backscatter from atmospheric Sodium layer at about 90 km altitude produces a point like artificial source at this altitude. The high optical quality requested for very fast optics, the severe constraints of the layout accommodation and the mass reduction made LTA a technological challenge that Galileo Avionica has been able to design, realise, align and test as requested. LTA will be positioned atop the secondary mirror unit of one of the four VLTs.

The aim of the presented LIGA-microspectrometer design is, to improve the spectral resolution and to achieve a high sensitivity covering at the same time a large spectral range. The footprint of the microspectrometer had to be increased to achieve these goals. To limit the increasing of the size of the system, the internal optical path was folded by introducing a mirror. The spectrometer is a grating spectrometer where the light is guided in a hollow waveguide. To improve the sensitivity of the spectrometer, the losses in the hollow waveguide had to be limited. As these losses increase with the number of reflections in the waveguide, a collimator lens in front of the entrance slit was introduced to realize a quasi free space propagation of the light in the waveguide. The concept of this microspectrometer, its characteristics, dimensions and key elements, such as entrance slit, collimator lens, hollow waveguide, optical path folding and decoupling mirror, are explained. Also the result of the photographic characterization of the microspectrometer is shown.

An optical set-up for electronic speckle pattern shearing interferometry (ESPSI) using a photopolymer diffractive optical element as a shearing element, is presented. A laser beam illuminates the object at an angle to the normal to the object surface. The holographic diffraction grating is placed in front of the object. The zero and the first order of diffraction form the image and the sheared image of the object. The images are imaged onto the CCD camera, whose optical axis coincides with the normal to the object surface. The field of view is limited only by the dimensions of the photopolymer plate. The photopolymer diffractive element is characterised by low level of light scatter and diffraction efficiency of 60%. The simplicity of the proposed new shearing interferometer is manifested by the extremely small number of components required - a coherent light source, a holographic optical element and a CCD camera.

This paper describes the whole process of designing, manufacturing and assembling the optics for an infrared pyramid wavefront sensor, called PYRAMIR. This sensor is built to work with the adaptive optical system at the 3.5 m telescope of the Calar Alto Observatory, Spain, which controls a 97 actuator deformable mirror. PYRAMIR is working in combination with an infrared science camera, which is used for observations. Since the wavefront sensor works in the near infrared (1.0 μm to 2.4 μm), the detector, the optics and all the mechanics are cooled to liquid nitrogen temperature. For this cryogenic condition, special care has to be taken for the optical design and the mounting of the lenses. We describe in detail the process from infrared optical design and cryo-mechanical engineering, to the final assembly of the opto-mechanical units and testing in the lab. Technical solutions are illustrated and the final performance is demonstrated.

A novel add-on device to a mobile camera phone has been developed. The prototype system contains both laser and LED illumination as well as imaging optics. Main idea behind the device is to have a small printable diffractive ROM (Read Only Memory) element, which can be read by illuminating it with a laser-beam and recording the resulting datamatrix pattern with a camera phone. The element contains information in the same manner as a traditional bar-code, but due to the 2D-pattern and diffractive nature of the tag, a much larger amount of information can be packed on a smaller area. Optical and mechanical designs of the prototype device have been made in such a way that the system can be used in three different modes: as a laser reader, as a telescope and as a microscope.

CMOS image sensors include control transistors in the pixel itself, which generally results in a square or rectangular shape in the design of the photo sensitive surface, which is thus much smaller than the total pixel surface. The CMOS process also results in the presence of a stack of layers (dielectric and metallic) with specific optical properties, deposited above the photo sensitive area. In order to focus the maximum number of photons on the optically sensitive area of the pixel, a micro lens is fabricated on the top of the stack. The aim of this study is to optimise the micro lens to maximise photon collection in the photodiode. Especially we have evaluated the influence of micro lens cross sectional and base shapes on the light focusing and sensitivity. For this study we used the optical modelling software ZEMAX (ray tracing) and modelled the CMOS image sensor by a simple optical system: micro lens, media ("stack") with particular optical properties and a photosensitive area. Concerning the cross sectional shape, our results show that it is important to optimise the process to obtain a spherical one. Furthermore, even though the photosensitive area is rectangular, the best base shape for the micro lens is not necessarily a square: a significant portion of the photon gain due to the base shape (square or octagonal) is lost in the non-sensitive area of the pixel. Moreover, the gain in sensitivity on-axis due to the larger size of a square base is relatively small, and is offset by a significant loss in relative illumination versus incidence angle.

Two novel objective types on the basis of artificial compound eyes are examined. Both imaging systems are well suited for fabrication using microoptics technology due to the small required lens sags. In the apposition optics a microlens array (MLA) and a photo detector array of different pitch in its focal plane are applied. The image reconstruction is based on moire magnification. Several generations of demonstrators of this objective type are manufactured by photo lithographic processes. This includes a system with opaque walls between adjacent channels and an objective which is directly applied onto a CMOS detector array. The cluster eye approach, which is based on a mixture of superposition compound eyes and the vision system of jumping spiders, produces a regular image. Here, three microlens arrays of different pitch form arrays of Keplerian microtelescopes with tilted optical axes, including a field lens. The microlens arrays of this demonstrator are also fabricated using microoptics technology, aperture arrays are applied. Subsequently the lens arrays are stacked to the overall microoptical system on wafer scale. Both fabricated types of artificial compound eye imaging systems are experimentally characterized with respect to resolution, sensitivity and cross talk between adjacent channels. Captured images are presented.

Planar integrated microoptical systems have been demonstrated for a variety of applications such as optical interconnects, sensing and security applications. Diffractive optical elements provide the necessary design freedom to optimize the optical performance of such systems along the folded optical axis. For enhanced optical efficiency it is necessary to combine diffractive and refractive elements within such systems. Hereby the refractive components provide most of the optical power while the diffractive elements are used as correction elements for optimized system performance. The integration of refractive components has significant consequences on the geometry of planar integrated optical systems as well as on the optical systems design. Based on this approach we present various designs for efficient planar-optical (phase-contrast) imaging systems. We compare various possibilities for the simulation of diffractive and holographic optical components and their integration in the design of planar microoptical systems. To this end we apply commercial design software (e.g. Zemax^TM, ASAP^TM) as well as self programmed tools.

Apposition compound eye camera objectives are one approach for a vast reduction of the optical system length of an imaging optical sensor. Despite imaging the complete field of view through one aperture like in classical lenses, these objectives split the overall field of view in separated channels which are located adjoined like in insect eyes. Due to the splitting each channel can be optimized for reduction of aberrations occuring under oblique incidence. A correction for astigmatism, field curvature and distortion occurring under oblique incidence can be accomplished by the use of anamorphic micro-lenses leading to an improved resolution of the camera objective. In contrast to regular arrays of equally shaped and equidistant positioned micro-lenses the parameters of the lenses like radii of curvature, center position and angular orientation are functions of the position within the array. These functions can be derived analytically leading to a complete description of the array parameters. We present design considerations for a chirped array containing 130x130 individually shaped ellipsoidal micro-lenses. Melting of photo-resist is employed as fabrication technology for achieving diffraction limited performance. Detailed considerations for the semi-automated layout generation of the photo lithographical masks as well as characterization data of first realized prototypes of the array are given.

The complete knowledge and description of light sources is a fundamental base of optical design. Partially coherent, paraxial light sources of homogeneous polarisation state are represented by the four-dimensional Wigner distribution function, which contains all information on amplitude, phase relations and spatial coherence. Hence, knowledge of the Wigner distribution enables the prediction of power density distributions after propagation through a wide range of optical systems by numerical simulation. A simple optical setup consisting of a spherical lens, a cylindrical lens, and a CCD camera can be used to experimentally retrieve the Wigner distribution function of a spatially confined light source by a tomographic reconstruction scheme. This paper briefly introduces the Wigner distribution and outline the reconstruction scheme. Measurements on partially coherent laser beams are presented including examples of successful predictions of power density distributions behind some optical systems.

The well tested and accepted ISO standard 11146¹ provides the measurement procedure to characterize the propagation properties of stigmatic and simple astigmatic laser beams which are intrinsically symmetric. The beam diameters are defined by the second order moments of the power density distribution which can be measured e.g. with a CCD-camera. In this standard the second order moments are used since the knowledge of these second order moments allows the calculation of the beam properties behind aberration-free optical systems with the well known ABCD-matrices. The new ISO/FDIS 11146-2² provides a new measurement procedure to characterize general astigmatic beams which are characterized by ten independent second order moments of their Wigner distribution. We present experimental results of the characterization of a general astigmatic beam and compare these results with theoretically calculated values. In this experiment a well characterized simple astigmatic beam is propagated through a cylindrical lens which is tilted with respect to the symmetry axis of the beam so that the simple astigmatic beam is transformed into a general astigmatic beam. This general astigmatic beam is characterized according to the new ISO standard. The measured second order moments are in good agreement to the theoretically calculated beam properties.

Earlier we presented an alternative approach for laser beam characterization, based on the decomposition of the field distribution at certain cross section of the laser beam into a system of orthogonal functions. As such orthogonal function systems we selected "natural" laser eigenmodes of either GL or GH type. The looked for strength of the individual modal components then can easily be achieved by measuring the output signal ("correlograms") of multi-channel correlation filters placed in a Fourier set-up, whereas the correlation filters themselves have been realized as DOEs by laser lithography. Meanwhile different systems of such GL and GH correlation filters have been designed, manufactured and experimentally tested with miscellaneous laser beams. Achieved results demonstrated a very good conformity between optical experiment and computer simulation. Attempts to compare results of our method with results of "standard" beam characterization methods (new ISO11146) indicated principal conformity, but illustrated the continuing demand for a sophisticated adjustment procedure for the filter during application. Recently such a sophisticated adjustment algorithm has been developed, implemented and applied to measured correlograms. This gives us the capability to evaluate with high accuracy even very complex correlograms, resulting from superposition of miscellaneous transversal modes. Exploiting a "tunable" Nd:YAG laser as mode generator for supply of pure or mixed GH modes, and evaluating the quality of the same laser beam twice, in one branch by our decomposition method and at the same time in the second branch by Second Order Moments method (new ISO 11146), demonstrates the strong potential of the decomposition method.

The ISO Standard 11146 has joined the various company specific standards into one set of procedures to determine laser beam propagation parameters. Due to the implementation of the standard, a lot of smaller and some critical measurement problems become visible. The main part of beam parameter calculation is the determination of the beam width based on the second order moments of the power density distribution. Due to the mathematical definition, the second order moments are sensitive to incorrect determination of the zero level of the detector. The signal to noise ratio also plays an important role. Other critical points are non-linearity and artifacts of the detector and the optical system itself. An example for an implementation of the ISO 11146 within the design of a real measuring tool is demonstrated. The PRIMES MicroSpotMonitor is a camera-based beam diagnostic system. It is ready to measure automatically even high power beams with dimensions down to the range of several micrometers. The constraints between the demands of the standard and practical application will be discussed.

Multi-pass amplification to the 10 joule level for a femto-second CPA laser system is aimed at diode-pumping Yb3+ doped fluoride-phosphate glass with an energy of 240 J at 940 nm. Collimated pump light of 1000 laser diode bars is focussed onto an a circular glass disk with 28mm diameter. A two-sided ring shaped assembly of diode stacks and attached optics is applied for longitudinal pumping. We developed a computer aided optimization routine for positioning single pump foci with size of 4 × 8mm2 to achieve a smooth homogeneously distributed top-hat shaped pump profile with a diameter of 18 mm. For monitoring purpose the pulse energy of each diode stack is measured with a solar panel placed behind a reflecting mirror.

In this paper, safety-related experiments with ultra-short laser pulses (down to 30 fs) on various components (goggles, curtains) for laser protection are presented. The damage and failure behaviour of protective devices has been investigated dependent on practical conditions such as pulse duration, laser fluence, pulse number, and repetition rate. The effects of laser-irradiation on materials can be roughly divided into transient ones like laser-induced transmission (LIT) or short-lived colour centres and permanent damages like the stable colour centres and ablation. The former effects are particularly important for transparent devices like laser goggles. To obtain a complete overview on laser safety issues and the prevention of failure there are two important fields of investigation: 1. the effects of laser radiation on human eyes and skin, and 2. on the possible protection materials. Both fields have been addressed during the recently finished German project SAFEST (safety aspects in femtosecond technology). The amount of safety data available in the ultrashort pulse region has been increased remarkably. This allows for a re-evaluation of known laser protection materials for this region of pulse durations and for the evaluation of new designs that promise high protection levels while being light-weight and convenient to use.

The coherent adding (tiling) of gratings is a promising alternative to large single gratings for highest-power CPA lasers. However, in order to obtain both temporally and spatially undistorted beam profiles it is necessary to align the mosaic gratings accurately to less than λ/20 with respect to one another. This paper is aimed at a thorough description of the alignment procedure, which uses both spatial and temporal properties of the laser beam to detect grating misalignments. The main emphasis lies within the analysis of the k-space, which becomes accessible by focussing the compressed laser-pulse or a monochromatic alignment laser, respectively. We present the effect of grating misalignments on both focal area and near field by propagating continuous-wave, monochromatic laser light through a misaligned tiled grating compressor.

We have developed a tool for the simulation of ultra-short laser pulse propagation through complex real optical systems based on a combination of ray-tracing and wave optical propagation methods, which can also be used as a design tool. The focussing properties of different lenses are analyzed and the results are demonstrated. A design for a special focussing optic will be presented. Its focussing properties are compared to a commonly used microscope objective in theory and experimentally.

A multipetawatt laser is in construction in France with a compressor scheme using diffraction gratings. With an original code which takes into account the imprecision range of the geometrical parameters during the fabrication process, we numerically optimize the mirror stack and study different groove profiles in order to reduce the electric field inside the solid materials. It is shown that among all the profiles which lead to good diffraction performances, the profiles with the highest groove depth and width values lead to the smallest enhancement of the electric field inside the solid materials with a decrease by a factor slightly higher than 2.5. Moreover, in view to reduce the mechanical constraints in the stack, an original setup using a metal insert between the substrate and the dielectric mirror is studied.

Autostereoscopic display devices with large visual field are of importance in a number of applications such as computer aided design projects, technical education, and military command systems. Typical requirements for such systems are, aside from the large visual field, a large viewing zone, a high level of image brightness, and an extended depth of field. Additional appliances such as specialized eyeglasses or head-trackers are disadvantageous for the aforementioned applications. We report on the design and prototyping of an autostereoscopic display system on the basis of projection-type one-step unidirectional holography. The prototype consists of a hologram holder, an illumination unit, and a special direction-selective screen. Reconstruction light is provided by a 2W frequency-doubled Nd:YVO₄ laser. The production of stereoscopic hologram stripes on photopolymer is carried out on a special origination setup. The prototype has a screen size of 180cm × 90cm and provides a visual field of 29° when viewed from 3.6 meters. Due to the coherent reconstruction, a depth of field of several meters is achievable. Up to 18 hologram stripes can be arranged on the holder to permit a rapid switch between a series of motifs or views. Both computer generated image sequences and digital camera photos may serve as input frames. However, a comprehensive pre-distortion must be performed in order to account for optical distortion and several other geometrical factors. The corresponding computations are briefly summarized below. The performance of the system is analyzed, aspects of beam-shaping and mechanical design are discussed and photographs of early reconstructions are presented.

A method of transformation of Bessel light beams (BLBs) with an arbitrary cone angle into beams having radially (ρ-) and azimuthally (φ- ) polarization is suggested and elaborated. This method is based on the use of interaction of radiation with a periodical medium having defect inclusion in the form of an anisotropic layer. It is shown that owing to variation of parameters of defect inclusions one can realise a controllable effect on interference maxima of transmission of the periodical medium. Due to the phase difference of orthogonal polarized eigen waves of in passing through every period of the medium, photonic band gaps (PBGs), corresponding to different eigen waves, are splitting and shifting with respect to each other. Such a shift can result in the overlapping of regions of significant reflection of one eigen mode with a region of high transmission of another eigen wave. This enables one to separate and consequently spatially select radially and azimuthally polarized Bessel light beams. An advantage of the suggested method of formation of ρ- and φ- polarized BLBs is the possibility of its realization for any wavelength. This is easily attained by tuning the cone angle of the incident circularly polarized BLB.

The reduction of contrast due to scattering by optical mounts and buffers was studied, especially for the systems that must work in the infrared region. When a particular optical system is optimized [1,2] up a specified field value the scattering effects introduced by optical mounts and buffers must be taken into account. The scattering effect plays an important role in the IR region where the influence of off-field effects is important. The contrast reduction due to scattering effects is not uniform with the object position, in other words the influence of scattering effects has field dependence. The scattering model used is based on the classical point of view of the scattering electromagnetic wave and it is adapted for optical evaluation using ray-tracing techniques. In order to test the validity of our scattering model we calculated the distribution of illumination produced for a laser beam in a plane-parallel plate with perfect scattering properties at the back surface. The comparison between the results obtained form our model and the analytical models permit us to extrapolate the use of our model in systems that involve more complex geometry. The model was applied in a four element IR objective with germanium and silicon lenses. In all the situations the contrast as a function of the field value was calculated, with and without the scattering effects. By contemplating the contrast loss, a better choice of materials, geometries and buffer positions can be made possible.

A countable set of linearly independent solutions of the paraxial wave (Schroedinger-type) equation is derived and given the name hyper-geometric modes. These solutions describe pure optical vortices that can be generated when a spiral phase plate is illuminated with a plane wave. The distinction between these modes and the familiar paraxial modes is that in propagation the radius of the former increases as a square root of distance and the phase velocity is the same for all modes. In the present work experimental results on trapping and rotation of 5-10 micron-sized biological objects (yeast cells) and polystyrene beads of diameter 5 μm using various laser beams are discussed.

The investigation of physical properties of new relaxor ferroelectric material of (1-x)Pb(Mg_1/3Nb_2/3)O₃-xPbTiO₃ (PMN-PT) single crystal has been carried out. It has been established the opportunity of existence of this crystal in two modifications, having tetragonal unit cell (space group P4mm) and cubic perovskite one (space group Pm3m) accordingly. Their lattice parameters were found. It has been established a thermal stability of the PMN-PT single crystals in wide temperature range (20-950°C). The results of optical investigations have shown, that the crystals have good transparency in wide spectral area from the visible to IR range. Dispersion of refractive index of PMN-PT crystal are calculated by the dispersion theory and Kramers-Kronig' relationship. Using interferometry method, extremely large linear electro-optic coefficients r₁₃~33 pm/V and r₃₃~80 pm/V were characterised for the crystal, having tetragonal unit cell. It has been discussed prospects of the material while creating different optical systems.

The results of a numerical simulation of a conventional and a modified Schwarzschild objective are illustrated in relation with their use as imaging systems in an extreme ultraviolet lithography setup. It is demonstrated that the degradation of the resolution on the wafer due to the unavoidable tilt of the mask to the axis can fairly be vanished by a counter tilt of the wafer. In particular, it has been analysed the Schwarzschild objective setup under implementation at the ENEA Frascati Center within the context of the Italian FIRB project for EUV lithography.

Introduction of diffractive optical elements (DOEs) opened the possibility to control field distribution in the cross-section of laser beam. In fact, by use of DOE one can focus the laser beam into predicted areas as well as form the beam with pre-given behavior propagation through waveguide medium. The diffractive micro- relief can be realized either on the separated substrate or directly on the waveguide surface. Some applications need the focusing of the output waveguided beam into predicted area. But generally, one can use diffractive micro-relief on the output of waveguide in the case of excitement of selected waveguide mode only. Another applications need selected waveguide mode excitement for fiber sensor sensitivity improvement. In the present talk it is suggested to use micro-relief on the input waveguide cross-section for selected mode excitement. The strategy of the search of waveguide mode with intensity distribution closed to the illuminating beam intensity distribution is suggested to be used. Corresponding numerical procedure is described. Computer simulation results are presented.

With enhanced performance of computing facilities the iterative design of phase diffractive elements (DOEs) has become widely accepted. A great number of up-to-date technologies for DOE fabrication make use of the approximation of the commonly continous DOE phase function by a picewise continuos (quantized) function. This is the reason why constructing iterative procedures for the design of quantized DOEs (DOEs with quiantized phase function) has become topical. Designing quantized DOEs with small number of quantization levels using Fienup-type iterative algorithms (or IFTA-algorithms) is hampered by the necessity to solve the diffractive theory inverse problem at every iteration. Besides, using of such algorithms cannot guarantee convergence to global optimum. The use of stochastic procedures does not make it necessary to solve the inverse problem. Thus, the DOE phase function may be sought for directly over a set of "technologically implemented functions," allowing the quantization errors to be avoided. Such approach can be used also in the case of another restrictions (restriction on the etching depth value, etc.) However, constructing a stochastic optimization procedure for a real DOE calls for solving a great number of direct problems, which in general may result in an unpractical coputational efforts. It seems worthwhile to consider how the stochastic DOE phase optimization can be used when solving the direct problem does not require great computational effort (e.g. for a radially symmetric DOE). This paper deals with application of the known genetic stochastic procedure to determine the optimum of the function of many variables to designing quantized DOEs focusing light into radially symmetric focal domains (focusing into a circle or flat-top). Computer simulation results are presented.

By using of polarization spectrum, a laser frequency stabilization system for Cr atom lithography was designed. In order to eliminate the noise and improve the signal-to-noise ratio, a Lock-in amplifier was used. Calculation shows that the frequency discrimination signal is a purely dispersive signal. The energy sublevel distributions of Cr atom, which are important for frequency discrimination signal as the designed system would be used for Cr atom lithography, were also discussed. The nuclear magnetic torque of Cr atom is zero, which in turn has no influence on the energy level of Cr atom. Calculation shows that several other factors, such as the isotopes and the earth magnetic field, had little influence on the energy level of Cr atom, indicating that they could be ignored in the current experimental system. Some factors which will influence the line width and the linearity of the discrimination signal are also discussed.

The development of optical design and analysis tools in a CAD software can help to optimise the design, size and performance of tomorrow's consumer products. While optics was still held back by software limitations, CAD programs were moving forward in leaps and bounds, improving manufacturing technologies and making it possible to design and produce highly innovative and sophisticated products. The problem was that in the past, 'traditional' optical design programs were only able to simulate spherical and aspherical lenses, meaning that the optical designers were limited to designing systems which were a series of imperfect lenses, each one correcting the last. That is why OPTIS has created the first optical design program to be fully integrated into a CAD program. The technology is available from OPTIS in an integrated SOLIDWORKS or CATIA V5 version. Users of this software can reduce the number of lenses needed in a system. Designers will now have access to complex surfaces such as NURBS meaning they will now be able to define free shape progressive lenses and even improve on optical performances using fewer lenses. This revolutionary technology will allow mechanical designers to work on optical systems and to share information with optical designers for the first time. Previously not possible in a CAD program you may now determine all the optical performances of any optical system, providing first order and third order performances, sequential and non-sequential ray-tracing, wavefront surfaces, point spread function, MTF, spot-diagram, using real optical surfaces and guaranteeing the mechanical precision necessary for an optical system.

Optical systems with variable optical characteristics (zoom lenses) find broader applications in practice nowadays and methods for their design are constantly developed and improved. Our work describes a methodics of the design of zoom lenses using the third order aberration theory. The proposed method makes possible to determine, which elements of the optical system can be only simple lenses and which elements must have more complicated design, e.g. doublets or triplets. It is also shown the method for optical system design that permits to calculate the radii of curvature and optical glass types for individual lenses.

The work deals with the influence of the wavelength of light on the values of wave aberration coefficients. It is proposed a methodics for calculation of the dependence of aberration coefficients on the wavelength, their interpretation and the connection to chromatic aberrations of the optical system. The relations for the calculation of chromatic aberration coefficients up to the fifth order are derived for the case of the imaging of axial point by the rotationally symmetric optical system.

The design process of optical systems requires to obtain residual aberrations of designed optical systems as small as possible. By analysis of the dependence of aberrations on the numerical aperture and field of view, it is possible to find such values of numerical aperture and field of view, where the residual aberration is zero. Such values of numerical aperture and field of view are called correction zones. The work theoretically analyses the described problem and equations are derived for expression of wave aberration coefficients using correction zones for aberrations of the third and fifth order. Finally, there was done an analysis of optimal values of correction zones and optimal position of the centre of reference sphere using derived equations. This analysis was performed for the case when it is required the maximal value of wave aberration to be minimized.

We analyze the performances of the most known phase filter design (the cubic phase plate) in wavefront coding systems with respect to on- and off-axis imaging. To this end, the PSF will be calculated at different off-axis positions and the contribution of coma and astigmatism aberration terms to its spatial variation will be evaluated. The study will include the subsequent digital image processing procedure as well, so that a clear idea of the overall system performance will be drawn.

In this paper, a new LCD polarized stereoscopic projection method with improved light efficiency is suggested. In the proposed system, two external polarizers are taken away from the conventional LCD polarized stereoscopic projection system by effectively taking into account of inherent polarization properties of the LCD projectors, so that light efficiency of the proposed system can be dramatically improved. From some experimental results with the Type-1 LCD projectors of NEC MT 1060R, it is found that the proposed system shows zero light loss in the polarization process and the resultant stereoscopic image projected from this system is 213%, 75% and 300% brighter than those projected from the conventional Type-1 LCD projector-based, Type-2 LCD projector-based and Type-3 projector-based systems, respectively.