This PDF file contains the front matter associated with SPIE Proceedings Volume 10690, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

Realistic image simulation is useful understanding artifacts introduced by lens aberrations. Simple simulations which convolve the system point spread function (PSF) with a scene are typically fast because Fast Fourier transform (FFT) techniques are used to calculate the convolution in the Fourier domain. This technique, however, inherently assumes that the PSF is shift invariant. In general, optical systems have a shift variant PSF and the speed of FFT is lost. To simulate shift variant cases, the scene is often broken down into a set of sub-regions over which the PSF is approximately isoplanatic. The FFT methods can then be employed over each sub-regions and then the sub-regions are recombined to create the image simulation. There is an obvious tradeoff between the number of sub-regions and the fidelity of the final image. This fidelity is dependent upon how quickly the PSF changes between adjacent sub-regions. Here, a different strategy is employed where PSFs at different points in the field are sampled and decomposed into a novel set of basis functions. The PSF at locations between the sampled points are estimated by interpolating the expansion coefficients of the decomposition. In this manner, the image simulation is built up by combining the interpolated PSFs across the scene. The technique is verified by generating a grid of PSFs in raytracing software and determining the interpolated PSFs at various points in the field. These interpolated PSFs are compared to the PSFs calculated directly for the same field point.

Trapping in poor local minima is a common problem in lens design. Conventional lens design approaches only lead the designer to one solution each time, and, especially when the designer has only limited experience, often better solutions exist. Global optimization algorithms such as genetic algorithms and simulated annealing have been used to find alternatives. However, these algorithms usually require significant computational power, and the designer has not much control over the process. Saddle point construction (SPC) method has been developed as a technique for adding lenses to the original system or to systematically switch from an existing local minimum to a different one. Earlier research has shown that in idealized lens design and simple practical lens design problems, SPC is able to effectively switch through the network of minima and get out of the poor local minima. However, the effectivity of SPC in the complex optical system has not yet been studied. We show in this paper that how SPC can be used to switch between local minima in a system with moderate complexity. The result shows that with SPC, it is possible to switch from a poor local minimum to better systems. SPC is also applied to a lithographic system to show how the switching mechanism works in highly complex systems.

The use of Abbe-numbers to choose lens materials is well established in the optical design community. Also the color correction impact of rotationally symmetric diffractive structures (DOE) has a simple expression as Abbe-number. Tables of relative partial dispersions facilitate the way of finding tri- or polychromatic corrections as well. But these tables are only available for important wavebands like VIS, MWIR and LWIR. Apart from these bands, Abbe-numbers and partial dispersions must be generated or, in case of DOE, given relations have limited evidence. An alternative approach is taken from the power-relation of the thin lens model. Its geometrical part is collected as curvature difference. The glass selecting part is the equation term containing the refractive index. The DOE-power depends on the first term of phase shift expansion and the wavelength. This first term fixes the geometry of the DOE. Relations to the step height of DOE in different wavebands will be provided. The sum of all optical powers (refractive and diffractive) has to be equal to the reciprocal of the focal length of the entire lens system. An arbitrary number of wavelengths might be taken into consideration, and a system of linear equations is generated. Doing so, the minimum number of power elements (refractive and diffractive) for a polychromatic correction can be determined. The number of respected wavelengths defines the kind of chromatic correction. Calculated single lens powers and DOE-geometry serve as reasonable starting points for the lens design procedure. In the dichromatic case (often called achromatic), the focal length is equal for two wavelengths. The proposed approach provides a system of two linear equations. The result in the VIS is the well-known crown/flint-combination without diffractive. An alternative solution – one-lens-design with DOE - is very common in the LWIR-band. Lenses with extreme long focal lengths need a trichromatic correction (sometimes also called apochromatic). The proposed approach generates a system of three linear equations: an equal power sum at three wavelengths. The result can be a three-lens-design without DOE having stronger curved surfaces and a less fast aperture. The alternative solution is a two-lens-design with DOE having a faster aperture. SWIR-examples will be provided. Using the proposed approach, the design of dual band systems starts with the request of four equal optical powers at boundaries of each waveband. It generates a system of four linear equations. The solution with the minimal expense is a three-lens-design using one DOE. A MWIR and LWIR-example with only three lenses will be provided. The proposed approach refers only to refractive index values of each lens material at interesting wavelengths. These values are available in electronic glass catalogues. The knowledge of Abbe-numbers is helpful to choose glasses, but the calculation of reasonable power distribution bases on refractive indexes. The proposed approach does not limit the number of respected wavelengths, since innovative multiband solutions can be simulated as well. This approach is a helpful tool for finding starting points for the lens design solutions with a minimal count of optical elements.

Some imaging optical systems include diffraction elements, both the even reflected stray light and multi-order diffraction stray light need to be considered at the image. They are related to the reflectivity and diffraction efficiency of optical surfaces. In this paper the binary tree is employed to describe the multifurcating tree in which each sampling ray’s information is kept. According to the multi-order diffraction efficiency, paraxial ray and real sampling rays are traced, and the calculating results are applied to analyze the stray light in optical systems including diffraction components, and then the stray light energy distribution at any space especially at the image can be obtained. A new calculated wavelength is used to replace the designing wavelength for binary optical elements to calculate the reflected diffraction stray light. Based on the principles above, the stray light analysis software is developed. By tracing and analyzing all sampling rays the positions of ghosts are shown, especially at image surface. In this procedure, the first surface of the system serves as the entrance pupil or stop, instead of the entrance pupil in original imaging system, so as to collect all sampling rays from all direction, in or out the field of view, and then all possible ghosts are obtained. According to the simulation, the glare shields or control methods can be designed.

Understanding the sensitivity of optical systems thoroughly can lead to improved tolerancing and compensation. An examination into a complex sensitivity analysis is shown. This analysis is used to improve the overall tolerancing and compensation of an optical system. We have developed a tool to facilitate this method of sensitivity analysis. An example of a novel compensation method is presented.

Straight and bent self-written waveguides (SWWs) are formed within a photomonomer mixture by means of a self-trapping effect when a single laser beam or two laser beams with tilt are propagated inside. These SWWs can be used as optical interconnects in integrated photonic circuits if two laser beams are launched in opposite directions into the photomonomer. In this work, two kinds of photo-polymerization models are implemented to simulate the SWWs. In the phenomenological model, the refractive index increases directly with actinic laser intensity, whereas the diffusion model has a more complex variation of refractive index profile which takes into account the individual redistribution of mixture components. Both these models are linked with a CrankNicholson based Beam Propagation Method (CN-BPM) to simulate the time varying light distribution within the polymer coupling structures. Differences are observed in the numerical simulation results for straight and bent SWWs with respect to the temporal evolution of refractive index within the mixture, corresponding beam intensity profiles and curing time. In addition, we show that a saturation of refractive index change leads to the polymerization of surrounding monomer and, as consequence, to corrupted light guiding. We report on the minimum refractive index modulation that is required for optimal light guiding within the SWW.

Phase space provides the natural formalism with which to formulate optical imaging problems as a system with constraints. We consider the general formulation of optical imaging problems and look at two examples. The first example is a completely asymmetric freeform prism that has titled surfaces. The second example is a GRIN media that is exactly solvable. This gives an alternative formalism to standard Seidel aberrations and nodal aberration theory that can be used in the design process.

Gaussian beamlet decomposition (GBD) and Gaussian beamlet propagation (GBP) have become accepted and well know methods for physical optics modeling, implemented in many commercial optical simulation software packages. Typical applications are the modeling of diffraction problems, involving collimated or low-divergence laser beams. For these applications and many more typical textbook examples, it can be shown that GBP and GBD offer an excellent match between experimental data and modeling results. For highly astigmatic laser beams, on the other hand, no published examples can be found, where GBP and GBD were used to model the resulting irradiance distribution and compared it to experimental data. A typical representative of such a system is a line laser system, which can be found in a variety of applications. Line lasers are used e.g. as pattern generators in triangulation-based 3D measuring systems, as light curtains in machine safety applications or for shape and volume measurements in logistics automation. Already in a very early product development phase, the knowledge of the irradiance distribution is crucial to ensure product functionality and product safety. Therefore, the measured irradiance data of a typical line laser system are compared here with the modeling results of a simulation software supporting the GBD and GBP methods. Under most conditions, there is a good agreement found between the measurement and simulation data, which suggests that GBD and GBP are useful tools in the design process of line laser systems.

The paper describes the use of stochastic ray tracing methods for synthesizing of photorealistic images, formed by optical systems of augmented reality devices, that combines image synthesized by the optoelectronic device with the surrounding environment. As the result of the research, new methods are proposed that make it possible to increase the efficiency and preserve the physical correctness of stochastic ray tracing methods in the task of the photorealistic images synthesis formed by optical systems. The authors show that in such cases the methods of direct stochastic ray tracing are more effective for visual modeling of the augmented reality picture on an example of the head-up display (HUD) optical system. The proposed approaches allow to combine direct, inverse and bi-directional stochastic ray tracing methods in one calculation. The work is illustrated by examples of the synthesized images observed in HUD optical systems.

In general, spherochromatism is denoted as the color variation of spherical aberration in refracting optical systems. If primary axial and lateral color is corrected, in most of the cases spherochromatism is the dominating chromatic aberration. However, in literature only some selected design examples and certain special cases were discussed, but a general analytical 3^rd-order description based on the chromatic variation of Seidel’s surface contribution for spherical aberration, has not been considered yet. Since furthermore, those selected design examples indicates that spherochromatism is expected to show induced aberration parts, caused by the primary color aberrations of the system, this paper introduces a new description of the 3^rd-order surface contribution for spherochromatism and gives a discussion on its dependencies on intrinsic and induced aberration parts.

Typical error functions used in optical design (imaging applications) exhibit non-linear landscapes (with refer- ence to the design parameters) with multiple minima. This makes optimization a challenging problem. Global search optimization algorithms could address such situations, but still local search ones are, in many cases, more convenient to avoid excessive computational cost. Local search algorithms highly depend on a suitable selection of the starting system configuration. In this work, a diapoint-based optical metric (without reference to the paraxial focus) is proposed to find the optimal starting point, in rotationally symmetric optical systems. The potentials of the idea are shown by means of simulations carried out in a cemented achromatic doublet that includes image plane location as a design parameter.

Optical glasses with certain inner quality e.g. low striae content are essential for good optical systems. A stria is a small local change in the refractive index inside the glass due to small local changes of the glass composition. A stria results in a wave front distortion that can cause a blurring of the image. The effect of striae inside optical glasses on different optical systems are simulated in order to value its significance. Such striae simulations turned out to be difficult and bringing the design software to its limits. Some pitfalls are discussed leading to criteria for trustworthy (reliable) simulation results. These criteria are shown and finally reliable simulation results for an eye piece used in a microscope are shown. Furthermore the results obtained in this publication lead to additional work on striae simulations.

In this paper, we are reporting a systematic investigation of striae tolerance in various optical systems. A surface-based phase plate model and a volume striae model are given to simulate the striae strength that introduces optical path difference. The striae could be modeled at an arbitrary location in the element and with both rectangular and cosine shape. Concerning the striae functionality, various criteria were investigated and combined for system analysis, which particularly demonstrate the impact of striae on resolution, distortion and chromatic aberration. Three characteristic optical system types, aperture-dominant, field-dominant and front aperture systems, are investigated in system tolerancing. Both the analysis of striae at different position and in different systems were implemented. According to the study, the impact of striae is related with the marginal ray, chief ray and material properties. Consequently, based on the quantitative analysis, recommendations for the right choice of glass striae grades could be given in optical system tolerancing, which is beneficial to both the optical designer and glass vendors.

Nanosats or CubeSats are emerging technologies corresponding to miniaturized satellites with a wet mass between 1 and 10kg. In this study, we explored the possibility of doing earth observation in the longwave infrared. The challenge is to integrate the longest focal length as possible in a 2U volume dedicated to the optical payload. Another challenge is to use a low cost, lightweight and low power consumption microbolometer which requires high apertures optics. For these volumes, there is a competition between refractive designs, often more compact when having high apertures, and reflective designs, having a lower mass and being easily athermalized. The choice is not obvious and we studied a telephoto refractive design and an off-axis Three Mirror Anastigmat (TMA) reflective design. The key technology for the telephoto design is the use of chalcogenide glasses whereas the key technology for the TMA is the use of freeform surfaces.

Smartphones are increasingly utilising a dual-camera setup, introducing the possible use of one or more specialised camera modules. The current work presents a smartphone camera designed for portraiture. In portraiture, it is desirable to have a natural Bokeh effect, resulting from shallow depth of field (DoF). Because DoF is inversely related to the square of diameter, the proposed lens has a large entrance pupil diameter and low F-number. To fit such a camera within typical smartphone housing, the design is doubly folded, resulting in a compact z-profile (phone thickness) of less than 5 mm, with a total ray path of 13 mm. Due to physical limitations, the field-of-view (FoV) is reduced; this is acceptable, considering the specialised application of the camera and attractively large entrance pupil diameter. With a focal length of 7.6 mm, the system is retrofocus, but could be considered telephoto in terms of its z-height, when compared to typical smartphone lenses. This proof-of- concept design is demonstrated here using glasses. Axial colour is controlled using two doublets. For compactness, the aperture stop is positioned between the first doublet and first fold mirror, also allowing balancing of lateral colour and distortion. For very compact applications, a fixed-focus version of this system was designed. However, considering the large focal length and diameter, the hyperfocal distance is unattractively large; hence, a slightly longer refocussing system was also designed. Refocus is achieved by moving the the second doublet, the power of which must be increased relative to the fixed-focus design|the power increase disturbs the aberration balance about the stop, and hence lateral colour and distortion increase slightly. Distortion remains below 5% and lateral colour should be possible to correct digitally.

In the context of environmental monitoring, it is very important to improve systems for the identification, assessment and management of environmental risks through the use and integration of analytical techniques combined with hyperspectral airborne sensing technologies. Remote-sensing applications are varied, but nevertheless an accurate mapping of the soil required the use of complex scientific instruments installed on airplanes or helicopters. The high integration of electronics, combined with the computing power of modern processors, allows the development of integrated and compact hyperspectral systems installed on drones.1 The drone era poses new challenges to optical devices design: they shall be light, compact and robust, easy to assemble and to control. This work explains the optical system design of HYDRACAM (HYperspectral DRone Advanced CAMera), an instrument devoted to hyperspectral imaging by using an electro-optical liquid crystal tunable filter combined with a commercial camera. The commercial ray tracing software Zemax/OpticStudio2 was used to perform the optical design. The main challenge was to manufacture a low cost optical device, containing the mass and the total length to suit a drone payload. A huge effort was made in order to combine strict constraints (such as the filter narrow entrance aperture and its acceptance angle) with ambitious optical performance requirements (high spatial resolution, large field of view). First, a description of the work done to find a trade-off between cost and opto-mechanical constraints is provided: the choice of the commercial objective, the choice of the custom lenses materials and shapes and some optical design original solutions are addressed. Then, the details of the optical performance analysis are discussed.

We present an ultra-compact infrared cryogenic camera integrated inside a standard SOFRADIR’s Detector Dewar Cooler Assembly (DDCA) and whose field of view is equal to 120°. The multichannel optical architecture produces four non-redundant images on a single SCORPIO detector with a pixel pitch of 15μm. This ultra-miniaturized optical system brings a very low additional optical and mechanical mass to be cooled in the DDCA: the cool-down time is comparable to the one of an equivalent DDCA without an imagery function. Limiting the number of channels is necessary to keep the highest number of resolved points in the final image. However, optical tolerances lead to irregular shifts between the channels. This paper discusses the limits of multichannel architectures. With an image processing algorithm, the four images produced by the camera are combined to process a single full-resolution image with an equivalent sampling pitch equal to 7.5μm. Experimental measurements on MTF and NETD show that this camera achieves good optical performances.

The extension of the operational frequencies of communication antennas to optical frequencies allows the transmission of very high data rates far beyond that of usual radio bands. The required optical communication antennas (OCAs) have at first glance some similarities to optical telescopes as used for astronomy, but their operational scenarios are very different. The biggest challenge from the system design point of view is the requested operation during daytime for communication with probes for deep space missions. They must allow communication with probes at very small SEP (Sun-Earth-Probe angle), where different strategies for tackling the solar irradiance are essential. The paper presents system design concepts for OCAs of very large (4m-8m) and extreme large (12m) clear aperture. Main subjects of discussion are the influence of alternate optical arrangements on heat rejection, seeing, stray light and caustic issues and the related degradation of the communication detector/receiver performance. Link budgets will be established for different aperture sizes. The paper concludes with a comparison of enclosure concepts and their influence on the design of the large optical components and the related cost aspects.

Our goal is to design a radiation resistant camera lens for color imaging capable to withstand ionizing radiations up to total doses of a few MGy. The latter cause damages in the internal structure of glass which can affect its optical transmission and refractive index (RI). On the one hand, the radiation-induced attenuation (RIA) mainly causes the glass darkening and image signal-to-noise ratio degradation and can be partially handled by choosing the most appropriate materials. On the other hand, the radiationinduced RI change (RIRIC) causes the blurring of the image which can be more harmful to the viewing applications. Indeed, typical RIRIC magnitudes of 10⁻⁴ to 10⁻³ mainly induce defocus on the image. Yet, no motorized elements have been shown to be resistant to radiations at the aimed dose levels. Similarly to thermal defocus in non-cooled thermal imaging, the impact of the RIRIC has to be studied during the design step of the camera lens. However, until comprehensive measurements on different glasses and under different types of radiations, the easiest way to foresee the lens behavior with respect to the RIRIC is to perform a parametric study of its response. We studied RIA and RIRIC effects on a dummy lens and show that a self-compensation of the lenses RI changes appears as possible. As this problem is very similar to the constraint of increased depth of field, we also studied the technique of wavefront coding to increase the lens tolerance to RIRIC.

In this paper, we consider methods of design and manufacture of diffractive optical elements (DOEs), generating socalled structured laser beams with predetermined amplitude/phase/polarisation distributions and perform transformation of those laser beams. Diffraction optics makes it possible to implement generation and control of the structured laser beams via single DOE and their combinations. We demonstrate several traditional methods that can be used to calculate a pure-phase transmission function of DOEs, both iterative and non-iterative. In addition, different technological processes for the manufacture of DOEs are used, including direct laser writing in thin films and lithography combined with plasma etching. The structured laser beams generated using DOEs provide new opportunities for large-scale highrate laser fabrication of nano- and microscale functional elements, as well as for the laser manipulation of microscale objects. The use of the structured laser beams in these applications (for example, radially/azimuthally polarised laser beams, optical vortex beams or beams with complex-shape transverse intensity distributions) allows advanced control..

Increasing the depth of field of a lens is one approach of relieving computational and mechanical refocussing mechanisms of lenses. In this paper we introduce a three element lens, consisting of an achromatic doublet, a singlet lens and a variable thickness element in the form of a refractive plate. The plate element provides an increase in depth of field comparable to 2.8 times that of a conventional lens. The lateral sag of the plate alters the optical path length for each bundle of rays with respect to the object distance so that all objects are imaged on to a fixed position detector. The surface is described by a combination of Zernike terms along the sagittal plane. Imaging is carried out with NIR narrow-band illumination where the fine details of the iris can be sharply captured in the image.

ZEISS ForTune is a photo mask tuning system for the semiconductor manufacturing industry. The tuning process improves critical dimension uniformity and mask image placement errors via intra–volume material modification at different depths within the mask material. For these applications, diffraction–limited spots of an ultrashort pulse laser are to be generated throughout the volume of the mask. In the present paper, we present an optical design concept for generation of diffraction–limited laser foci in thick specimens with refractive index n2. The optical design includes a microscope objective of medium–sized numerical aperture NA. A medium with refractive index n₁ ≠ n₂ is in between the microscope objective and the specimen – this index mismatch is the root cause for appearance of spherical aberration when diffraction-limited laser foci in different depths are to be generated. Thus, in addition to a proper paraxial focus position also a certain amount of spherical aberration must be corrected for. The amount of spherical aberration increases with focus position variation within the specimen, numerical aperture NA and the refractive index mismatch Δn = n₂ − n₁ of the specimen. The design concept includes an adaptive optical element such as a deformable mirror or a spatial light modulator. Due to limitations in their achievable optical path difference, it is essential to combine the adaptive element with an appropriate conventional focusing mechanism. Optical designs will be shown allowing for surprisingly thick specimens having a thickness corresponding to several thousands of Rayleigh ranges dR. Besides photo mask tuning, the presented optical design concepts can be used for different applications such as laser scanning microscopes, 3D printers using two-photon polymerization or vitrography.

In wavefront coding optical system, with the traditional cubic mask plate (CMP) which owns several extension times of depth of focus (DOF), it is difficult to manufacture. With the symmetrical surface type mask plate which can be machine relatively easily, but it presents small multiples of the extension of DOF. In this paper, it makes a presentation of mask plate design by user defined surface(UDS) type where it has an easy mechanical process and several multiples of extension of DOF. It presents the analytic expression by calculation and its DLL data file which is adapted to ZEMAX. It also performs a simulation experiment based on the three mirror Cassegrain(TMC) wavefront system. The experiment results indicate that instead of the traditional mask plate, the UDS surface mask plate can obtain a larger ratio of extension of DOF and increase the valuable types of mask plate surfaces. What is more, it decreases the surface mechanical difficulty compared to the asymmetrical surface mask plate. The type of UDS surface has the unique design and the convenience manufacturing, which is of great value in both application and research.

The advance progress of the visible light networking systems requires powerful and new devices that enable high data rate light transmission with low losses. Therefore, we introduce a new design for a 1×8 green light intensity splitter based on the multimode interference coupler (MMI) in a gallium-nitride (GaN) - silicon-oxide (SiO₂) slot waveguide structure. Simulation results show that after a propagation length of 16.55μm the power of the green light signal (536 nm) is split into eight output beams with equal power and low transmission losses of 0.11dB. In addition, the splitter operates in the visible light spectrum from 460-670nm. Therefore, this device can increase performance in network communication systems that work in the visible light range.

The Multi Conjugate Adaptive Optics RelaY (MAORY) is foreseen to be installed at the straight through focus over the Nasmyth platform of the future Extremely Large Telescope (ELT). MAORY has to re-image the telescope focal plane with diffraction limited quality and low geometric distortion, over a field of view of 20 arcsec diameter, for a wavelength range between 0.8 μm and 2.4 μm. Good and uniform Strehl ratio, accomplished with high sky coverage, is required for the wide field science. Two exit ports will be fed by MAORY. The first one is for a wide field Camera that is supposed to be placed on a gravity invariant port with an unvignetted FoV of 53 arcsec x 53 arcsec where diffraction limited optical quality (< 54nm RMS of wavefront error at the wavelength of 1 μm) and very low field distortion (< 0.1% RMS) must be delivered. The requirements regarding the optical quality, distortion and optical interfaces, together with the desire of reducing the number of reflecting surfaces (and consequently the thermal background), optics wavefront error (WFE), overall size, weight and possibly cost, drove the design to have 2 Deformable Mirrors (DMs) with optical power. The Post Focal Relay (PFR) is also required to split the 589 nm wavelength light of the Laser Guide Stars (LGS), used for high order wavefront sensing, by means of a dichroic that lets the light of 6 LGSs, arranged on a circle of about 90 arcsec diameter, pass through and reflects science beam. Behind the dichroic an objective creates the LGS image plane for the WFSs channel. We present in this paper the optical design and the tolerance analysis of the PFR and the objective. The tolerance analysis concerning the manufacturing and the alignment precision is also shown.

Complex endoscopes which utilize optics with less than 1.5 mm diameter have an elevated risk of failure. Therefore, to ensure functionality and minimize risk proper design, optomechanical analysis and modelling must be performed while taking into consideration current manufacturing capabilities. Our endoscope is designed to perform Optical Coherence and Multiphoton Microscopy (OCM and MPM) which are powerful endoscopic imaging techniques used to characterize tissue. Separately each imaging technique has limitations when used by itself; however, this design combines these two modalities into a single optical system to work in synergy achieving both high sensitivity and specificity for diagnosis at the point of care. The optical design features two optical paths with different numerical apertures (NA) through a single lens system with a scanning optical fiber. The dual path is achieved using dichroic coatings embedded in a triplet that functions in a telescope like fashion. A high NA ~0.44 path is designed to perform OCM and MPM while a low NA ~.18 path is designed for the visible spectrum to allow navigation of the endoscope to areas of interest. We present the optical design of the endoscope, optomechanical considerations, manufacturability, stress and temperature effects. All these factors may be a source of problems in such small optics utilizing rare materials such as ZnS MS lenses. While very tight tolerances were the driving factor for the manufacturability of this system, temperature and stress must also be evaluated to obtain a better idea of the durability of the endoscope at the point of care. While it is challenging to evaluate the real performance of multimodality endoscopes, the models ensure that the system is designed for the expected imaging techniques, providing acceptable imaging across the entire field of view. Finally, we will give insight on what lessons were learned during the design, analysis, lens manufacturing, and assembling processes of the endoscope to provide a baseline of parameters to take into consideration when designing such complex small optical systems.

Digital holographic microscopy uses interference patterns produced by the object and reference waves to computationally reconstruct both amplitude and phase of light reflected from a sample under study. The phase information recorded for each pixel can be converted to a height profile map, yielding a three-dimension image of the sample. Holographic imaging of layered structures, where layers are separated from one another by the axial distances exceeding the wavelength of imaging light, is challenging. Software based 2π phase discontinuity unwrapping, which relies on the gradients produced by the slowly varying sloped surfaces in the sample, is generally impossible. Additionally, dual wavelength phase unwrapping is complicated by the fact that if the layers are not sufficiently reflective, the unwrapping based on the comparison of two single wavelength phase images is unreliable. We present the design of a simultaneous dual wavelength digital holographic microscope, where the phase imaging of each individual layer is performed by a single wavelength, and then the axial distance between all layers is determined based on the comparison between the phase maps produced by each wavelength. By combining two interferometers within one setup, we could acquire two phase profiles simultaneously, enabling fast measurements. We demonstrate that this method is particularly well-suited for imaging of multilayered electrode structures embedded in glass, which contain both high and low reflectivity features.

Polymeric materials with optical properties are introduced widely into development of novel and complex optical devices. Applications include various imaging and illumination systems, medical devices, scanning and recognition of barcodes, fingerprint scanners, motion and presence sensors, CCD cameras, laser collimation systems, etc. To achieve high performance of optical systems combination of components made of conventional optical glasses and polymers is proposed. Such hybrid lenses could have decreased aberrations and improved image quality as well as be more compact and lightweight. Technological aspects of optical glass and polymer combination are observed in the paper. Computer modeling of a high-aperture hybride micro-lens using Zemax software is presented. Selection of appropriate optical polymers is described. Discussion of effective introduction of polymer components into the lens design is provided.

We provide an overview of the method of confocal mirror design and report new advances with respect to pupil imagery. One example illustrates the design of a system confocal of the object and image, and another illustrates the design of a system confocal of the pupils. Stop shifting formulae are provided.

In this paper, we compare a standard wide angle system design to an array of four off-axis micro optics systems. The reference system is a single x/y-symmetric optical system to reach full field of view (FOV) of 140°×170°. To obtain the same FOV an array of four off-axis systems, consisting of tilted and decentered freeform elements, with small sub FOVs is designed. The system design is such that a production via 3D-two-photon printing is possible. We compare the performances of the standard system to that of the array of off-axis systems.

In this paper, a lens system is presented, which requires just little space and has a high degree of flexibility in terms of the achievable focal length range. The well-known principle of the Alvarez lens has been newly taken up and enhanced. As a result, it is even possible to achieve a diffraction-limited imaging quality. However, manufacturing such nonrotational symmetric surfaces has many challenges to overcome, which should be discussed. Furthermore, valuable results of the manufacturing process of these freeform surfaces are presented.

The aberration fields of general systems of spherical components have been well studied in the context of nodal aberration theory by Thompson et. al. In this paper we follow the ideas of nodal aberration theory in the case of decentered and tilted anamorphic systems to the point where new effects occur, that are specific to anamorphic systems. This is used to qualitatively describe the aberrations of such systems, which turn out to be manifold and complex.

Various global optimization methods are available for the automatic design of optical systems. However, these methods are not specifically tailored at freeform systems with a large number of variables. This paper presents a novel method for the automatic design of optical systems which is based on Particle Swarm Optimization (PSO). PSO was originally introduced in 1995 to model the interaction of individuals in a swarm or a flock of birds. The optimization of a problem is performed by iteratively improving a candidate solution with regard to a specific merit function. A collection of candidate solutions, called particles, move around in the search space according to simple mathematical rules. The movement of each particle is influenced by its local best known position and by the best known positions found by other particles. Repeating this process is expected to guide the swarm to the best solutions. Important aspects of PSO are the communication of the particles with each other and the ability to learn from the experience of the swarm. A PSO algorithm has been implemented in a custom optical design software. In the application to optical design, each particle represents an optical system in the multi-dimensional parameter space. The merit function is a measure for the quality of the optical system. The application of PSO is demonstrated through several examples with and without freeform elements. The results prove that the proposed method is an excellent tool for the optimization of freeform systems with a large number of variables.

This paper presents the design of a novel varifocal freeform optics consisting of two lens bodies each with a helical-type surface structure of azimuthally varying curvatures. This arrangement allows for tuning the optical refraction power by means of a mutual rotation of the lens bodies around the optical axis. Thus, the refraction power can be tuned continuously in a defined range. The shape of the helical-type surfaces is formed by a change in curvature subject to the azimuthal angle α. At the transition of the azimuthal angle from α = 2π to α = 0, a surface discontinuity appears. Since this discontinuity will seriously affect the imaging quality, it has to be obscured. In the initial state, i.e. zero-degree rotation, the curvatures of the opposing surfaces result in a specific refraction power, which is constant over the entire circular aperture. Rotating one of the lens bodies by an angle φ around the optical axis will change the opposing curvatures and result in a change of refraction power. Two circular sectors with different tunable optical refraction powers are formed, thus resulting in a tunable bifocal optics. Obscuring the minor sector will result in a tunable monofocal rotation optics. In contrast to conventional tunable lens systems, where additional space for axial or lateral lens movement has to be allocated in design, rotation optics allowing for a more compact design. A simulative performance analysis of the rotation optics in dependence of the maximum rotation angle will be presented as well as an approach to design-for-manufacture.

The application of freeform elements in optical systems increases the number of design variables. In order to use the additional degrees of freedom most efficiently for correcting the system, the optimization process requires a guidance from the lens designer. The knowledge of aberrations generated in the system provides insights for selecting the best starting configuration as well as for choosing the position of the freeform element. In this work we use a new numerical method [Oleszko et al., JOSAA Vol. 34(10), 1856 (2017)] to study surface-by-surface contributions to the total wave aberration of freeform optical systems. Surface contributions are divided due to their origin into intrinsic, induced and transfer components. The study of intrinsic and induced effects assists in finding design solutions corrected for aberrations of orders higher than the fourth in the expansion of the wave aberration function. In contrast to the analytical approach, the method does not incorporate the field dependency into the wave aberrations and the error of the chief ray is studied separately. That allows to visualize the distortion of the image grid at the intermediate image planes.

Driven by the development of freeform imaging systems, we have combined several concepts and techniques from the literature to analytically generate unobscured freeform starting point designs that are corrected through the third-order image degrading aberrations. The surfaces used in these starting point designs are described as a base off-axis conic that images stigmatically for the central field point, also known as a Cartesian reflector, with an aspheric departure “cap” (quartic with the aperture) added to the base off-axis conic to correct for the third-order image degrading aberrations. Once the aspheric caps are added to the surfaces, the system is then optimized using higher order freeform terms while leaving second-order terms frozen to preserve the focal length of the system during optimization. This technique is used to survey the three-mirror freeform imager solution space. Several systems that are the result of this technique are shown, with different numbers of internal images, internal pupil conjugates and folding geometries.

The development in optical manufacture, alignment and testing has enabled the increasing use of freeform surfaces in all kinds of optical systems. The demanding system requirements need the involvement of optical surfaces that is able to provide more degrees of freedom. For better and more efficient use of the freeform surfaces, the understanding of freeform surfaces from all perspectives is necessary. We therefore study the impact of optimization strategy and freeform location on typical optical systems for varying applications. The uses of different optimization strategies, as well as the choice of locations for placing one or two freeform surfaces are considered. Their respective impacts on the final system performance are analyzed according to different aberration constitutions. By concluding all findings, we present some general rules for using and optimizing freeform surfaces in real design work. In the end, a work flow that gives instructions on how to use freeform surfaces in system design is presented.

In the present paper we demonstrate the approach to use a holographic grating on a freeform surface for advanced spectrographs design. On the example POLLUX spectropolarimeter medium-UV channel we chow that such a grating can operate as a cross-disperser and a camera mirror at the same time. It provides the image quality high enough to reach the spectral resolving power of 126 359-133 106 between 11.5 and 195 nm, which is higher than the requirement. Also we show a possibility to use a similar element working in transmission to build an unobscured double-Schmidt spectrograph. The spectral resolving power reaches 2750 for a long slit. It is also shown that the parameters of both the gratings are feasible with the current technologies.

Mapping and quantifying lunar water ice addresses one of NASA’s Strategic Knowledge Gaps to understand the lunar resource potential for future human exploration of the Moon. Lunar Flashlight is an innovative NASA CubeSat mission dedicated to mapping water ice in the permanently-shadowed and occasionally-sunlit regions in the vicinity of the lunar South Pole. Lunar Flashlight will acquire these measurements from lunar orbit using a multi-band laser reflectometer composed of an optical receiver aligned with four lasers emitting different wavelengths in the shortwave infrared spectral region between 1 μm and 2 μm. The receiver measures the laser radiance reflected from the lunar surface in each spectral band and continuum/absorption reflectance band ratios are then analyzed to quantify water ice concentration in the illuminated spot. The receiver utilizes a 70×70-mm, aluminum, off-axis paraboloidal mirror with a focal length of 70 mm, which collects the incoming light onto a single, 2 mm diameter InGaAs detector with a cutoff wavelength of 2.4 μm. We present the optical and mechanical designs of the receiver, including its optimization for rejection of solar stray-light from outside its intended field of view. This highly mass- and volume-constrained instrument payload will demonstrate several firsts, including being one of the first instruments onboard a CubeSat performing science measurements beyond low Earth orbit and the first planetary mission to use multi-band active reflectometry from orbit.

In the frame of the Sentinel-5 mission, Leonardo is developing the Short-Wave Infrared Spectrometer (SWIR-SS), part of the UVNS instrument foreseen to be embarked on board of the MetOP-SG satellite. S5 instrument objective is to monitor the composition of Earth atmosphere by taking measurements of trace gases and aerosols impacting air quality and climate, providing daily coverage of Earth atmosphere at an unprecedented resolution. SWIR-SS baseline architecture is a pushbroom imaging spectrometer with two channels,[1589÷1676] nm and [2304÷2386] nm, with a spectral resolution of less than 0.25 nm. At the object space is located a Slit-Homogenizer, a special component which guides the optical path across the slit in order to mitigate radiometric errors arising from scene heterogeneity. Its behaviour introduces an astigmatism which is corrected at collimator level by making use of a cylindrical lens. Light is then guided towards the dispersers and is focused onto the detector by the cameras lens. Pupil anamorphism, smile and keystone due to dispersers, immersed gratings, are corrected by using a prism and combining the distortion/lateral color of collimator and focusing cameras in both optical channels. A low pass filter at the dichroic splits the wavelengths, while, for each channel, two successive coatings on front and back faces of the prisms select the band and mitigate outof- band straylight. The design has the purpose to keep the alignment of each subsystem simple, as no aberration compensations have been foreseen between collimator and focusing camera. It shows robustness, stability vs temperature and high optical quality.

The optical design of the Moons And Jupiter Imaging Spectrometer (MAJIS), is discussed. MAJIS is a compact visible and near-infrared imaging spectrometer covering the spectral range from 0.5 to 5.54 μm (split into two channels), designed for the Jupiter Icy moons Explorer (JUICE) mission. The MAJIS optical layout is constituted by a TMA telescope shared between the two channels, as well as the slit and a collimator, a dichroic filter that splits the light between the channels (VIS-NIR and IR), each one endowed with its own grating, objective and detector. A flat mirror mounted in a Scan Unit before the telescope allows scanning the line of sight in a direction perpendicular to the slit. The collimator has a Schmidt off-axis configuration, with a specular correcting plate for each channel (the dichroic is inserted between the collimator primary mirror and the correcting plate). With the same conceptual layout in both channels, the collimated light is reflected by a flat ruled grating and crosses a completely dioptric objective. The objectives have the same focal length of the collimator, so both spectrometers have unitary magnification. A linear variable order rejection filter is placed in front of the detector so to reject the higher orders dispersed by the grating. A calibration unit allows radiometric and spectral calibration of both channels, with an incandescent lamp and a black body illuminating a common diffuser. Calibration is realized thanks to an extra-rotation of the Scan Unit. The developed design is optimized to work at cryogenic temperatures, with a good optical quality along the whole FOV and a good correction for transverse chromatic aberration and distortions.

The article deals with radiation-resistant television system located on the robot arm and designed for positioning of a gripper, for collecting and retrieving foreign objects (including nuclear fuel element’s fragments) located in the protective chamber of a nuclear power plant. Performing sequential necessary movements by arm, wrist and gripper of the manipulator nuclear fuel element’s fragments or objects are captured. By consecutive movement of arm, and wrist manipulator is moved to the position for the extraction from mine - arm is moved to the zero position, control is performed with the indicator on the control panel. Control of manipulator's components position and lifted objects is also visualized by means of a television system. After that, the manipulator is lifted from the mine of the protective chamber at low speed. The gripper can be replaced if necessary. Three cameras (two on a wrist and one on a forearm) are mounted on the manipulator to overview surrounding environment. The cameras located on the articulated arm have a mechanical angle adjustment. Each camera has individual focal length adjustment to provide sharpness in capture plane. Together the three cameras provide a panoramic view, side view and top view of a captured object. Each camera is equipped with built-in LED illuminators allowing to work without external lighting.

The paper conducts the new method of pipeline's inner surface control. The 3D model of the area can be built using laser profilers. Surface profile is the line of intersection of the plane having a predetermined orientation, with a given surface. Having a set of profiles, a surface relief can be built. Analyzed surface's profilogram in digital form is generated by computing system profiler on the distorted image profile. Besides the development of 3D measuring techniques for inline inspection leads to increasing of the speed of checking pipelines as a lot of data can be obtained from engineering surfaces in a short time.

We consider an on-axis AR optical system and its design process. As a source of light and imagea monochromic-green AMOLED SXGA micro-display is used. Size of display is 15.36 x 12.29 mm (19.67 mm diagonal, 0.77'') with pixel pitch 12 μm. For this project we consider the system with the field of view 30° and the minimum pupil diameter 10 mm. Usually AR systems based on off-axis layout with decentered and tilted elements and surfaces, this may add difficulties during mechanical mounting.However, on-axis system is possible based on spherical semi-transparent combiner together with additional plane mirror. Dimensions of designed system are suitable for head-mounting and the systemis simpler to produce and construct comparing to analogs. Although such systems are well known we present a design procedure and research of the element parameters which can be useful for future design in various areas.

The article is devoted to problems of design an optical system for an additive machine. The article discusses the possibility of applying different types of laser sources. It is proposed to use laser diode bars stack as a more efficient source. There are shown the results of attempts of modeling optical system in Zemax. There are shown and described the main elements of such a system. The study also considered the method is assembling a system for efficient ray tracing from laser diodes bar.

Laser gyroscope is an optical gyroscope with broad application prospects on inertial navigation field. When the application environment of laser gyroscope changes, its performance will be affected. When the temperature changes, the laser gyroscope’s core part - ring resonator cavity will have thermal deformation, so the position of the mirror on the ring resonator cavity will simultaneously change. This will result in the change of optical path, then affect the performance of laser gyroscope. Therefore, it is necessary to study the effect of temperature to the ring resonator cavity. In this paper, the temperature field and the coupling field of the ring resonator cavity of laser gyroscope are simulated and analyzed on the ANSYS Workbench 14.0 platform. The temperature field distribution and deformation of the ring resonator in different temperature environments are studied. According to the simulation results, with the increase of temperature, the deformation of the ring resonator increases linearly in the fixed direction. In addition, the influence of the parameters of the ring resonator cavity on the deformation is studied. The material of the cavity—glass-ceramics’s deformation is linearly related to linear expansion coefficient and Young’s modulus. However, its correlation with thermal conductivity, density and Poisson's ratio is not obvious.

Augmented reality systems are becoming very popular nowadays. Head-mounted displays can be used in different fields from entertainment to educational purposes and medicine visualization. In game industry HMD is the best way to combine virtual scenes with real world. Usually FLCOS, AMOLED and other microdisplays are used as a source of image. Such systems require especially designed optical layout to work with certain microdisplay. In virtual reality systems smartphone with special program on it is used as the image generator. In this case the program divides screen into two parts, each part for the one eye. The same idea can be applied in see-through head-mounted displays. Thus, the main object of the research is to analyze the possible optical schemes of the HMD which can work with a smartphone and provide characteristics suitable for the augmented reality.

The paper considers afocal compensators correcting various aberrations of optical systems such as spherical aberration, coma, astigmatism, surface curvature, chromatic aberrations. For illustration, the considered optical compensator schemes are reproduced.

We design an omnidirectional optical system that is composed of pseudo-Cassegrain collecting mirror part making narrow field of view(FOV) and a reverse pseudo-Cassegrain imaging mirror part, which can be used simultaneously in visible and long wavelength infrared(LWIR) light. The FOV is set to 40° to 110° and the F/number is 1.55. Because a CMOS sensor (CMOSIS, CMV2000) for visible and a micro bolometer sensor (semiconductor device, Bird 384) for LWIR are chosen, respectively, the common size of image should be determined by 5.9 mm × 5.9 mm. After the optimizing design, the ratio of the image height about two cases of 40° and 110° is 48.97 %. We can obtain that two MTFs for visible and LWIR at 20 lp/mm about the FOV of 110° are 0.425 and 0.385, respectively. The total length of this system is about 280 mm. When the MTF at 20 lp/mm and 110° is 0.3, the cumulative probabilities of the tolerance in visible and LWIR are 90.69 % and 99.79 %, respectively. After the athermalization analysis in the temperature range of - 32°C to 55°C, we choose the secondary mirror of the imaging part as a compensator to improve the collapsed MTF.

The system of AR became very popular for educational, military, entertainment and other areas. There are many possible variants of organization the optical part of such schemes. The very important part of the system is a combiner, that is an element which imposes augmented image over the surrounding environment. The power combiner helps to increase the eye relief, but in the case of the tilted power combiner, it adds a rather large amount of off-axis aberrations. These aberrations should be corrected by the following part of the system. Many ways of composing the system with tilted power combiner have been considered and can be found in modern literature. We consider special types of aberrations added by the curved combiner and discuss the ways of the correction. We also analyze possible layouts and their properties for using together with FLCOS and AMOLED microdisplays.

The implementation of modeling and research for image comparison methods is necessary for subsequent quality assessment of structures reconstructed with Fresnel hologram projectors, it will allow to select the optimal parameters of the optical circuit and the level of binarization of the hologram. The purpose of the paper is to research the comparison methods for planar images reconstructed with Fresnel hologram projectors with the original object. In this work, the methods of pixel-by-pixel comparison of images and methods of comparing images by histogram are considered. As a numerical criterion for the methods of pixel-by-pixel comparison, the RMS value was chosen. The smaller the RMS value, the more the restored image is similar to the original object. When considering the comparison of methods for image histograms were reviewed by comparing the histograms: correlation method, chi-square method, intersection method, the Bhattacharya distance method. For work, two experiments were performed, during which the most optimal binarization threshold was determined for planar images reconstructed with Fresnel hologram projectors, by comparing them with the original object. In the future, it is planned to implement a correlation comparison of images and compare images in the presence of defects: blur and possible artifacts of different nature.

In the work designing the head mounted display with AMOLED image source is considered. The properties of the image generator influence greatly on the characteristics. Due to it is self-luminous and has small sizes, AMOLED microdisplay provide to the optical engineer possibilities of designing compact and high-quality systems. Another one important element in the HMD system is the combiner: applying power combiner allows us to provide sufficient eye-relief, but its power and the form defines the principal layout of the system and aberration balance. We consider the cases of elliptical and spherical form of a combiner, discuss the aberrations for both cases and show the procedure of designing of the HMD system that uses AMOLED display as an image generator.

The optical design as a result of the synthesis of optical elements with known base aberrations properties is the basis for the unification of optical systems of objectives for microscopes. Technical parameters, optical circuits, optical and mechanical structures are subject to unification.

Development of a parametric model of an optical system consisting of 2 and 3 reflective surfaces and its analysis are considered in this paper. The construction of a parametric model is necessary to simplify the initial stage of designing optical systems. The basis of the parametric model is built by replacing reflective surfaces on thin components equivalent, in which a three-mirror system can be written using an external virtual axis angles (zero) beam with the optical axis. To solve the problem of minimizing aberrations, the theory of third-order aberrations developed by Professor G.G.Slyusarev is used. As a result of working is a universal equation, describing the entire variety of optical systems of three thin mirror components forming a flat image, the design parameters of which depend on the 3 coefficients that enter the equation. The use of the obtained parametric model of an optical system consisting of 3 reflecting surfaces makes it possible to simplify the stage of the initial synthesis of mirror optical systems and to obtain an initial version of a system free from spherical aberration, coma, astigmatism and curvature of the image.

In the present paper we consider a family of unobscured telescope designs with curved detectors. They are based on classical two-mirror schemes – Ritchey-Chretien, Gregorian and Couder telescopes. It is shown that all the designs provide nearly diffraction limited image quality in the visible domain for 0.4º×0.4º field of view with the f-number of 7. We also provide a brief ghost analysis and point on special features of the systems with curved detectors. Finally, the detector surface shape obtained in each case is analyzed and its’ technological feasibility is demonstrated.

In the present paper we consider an optical design of a head-mounted display with a free-standing holographic image combiner. The optical system works with a 24°×18° field of view and a 6mm pupil providing energy concentration up to 89% for a 20μm-pixel. The combiner represents a volume-phase reflective hologram recorded by two point sources. We demonstrate that the recording and replay angles for the hologram considerably vary across the surface, that causes perturbation and overall decrease of the diffraction efficiency. A revised optical design is presented. It provides a higher hologram efficiency together with a better image quality and decreased decenters of the components. The resultant gain in the median efficiency is factor of 5.3.

We describe a concept of a satellite imaging spectrometer dedicated for monitoring of the Earth atmosphere operating in the visible and near ultraviolet spectral range. The instrument targets measurements of total ozone as well as other gases (nitrogen dioxide, oxygen and its dimer etc). The instantaneous field of view (IFOV) across track reaches 100° allowing to obtain global daily maps of trace gases content when operating from a typical orbit. The optical concept and design of the instrument, which consists of the entrance unit, two spectrometric channels (for two wavelength ranges) and the calibration unit are described. We also discuss the results of the optical modeling, confirming the proposed characteristics: the spectral resolution of 0.3 nm for the range 300 – 400 nm and 0.5 nm for the range 400 – 800 nm. The angular resolution is ~ 0.5° in both channels that corresponds to ~6×6 km area on the Earth surface for nadir direction from a 700-km orbit.

The dominant free space optical (FSO) system adopts an optical fiber as a light transfer unit for transmitting or receiving of communication or beacon signals. The optical fiber is usually placed in a pinhole fiber connector which prevents direct measurement of optical instruments. Traditional test method fails to guide the accurate alignment of an FSO system. Here we propose a new method for point spread function (PSF) modeling by fiber coupling efficiency measurement. First we show the convolution effect of a multimode fiber with a numerical simulation using a focal spot with uniform irradiation. The coupling efficiency map versus the lateral translation has a flattop at the center and drops to zero at the edge, by which the focal spot diameter can be determined. A further simulation shows that the beam profile of a focal spot with rotational symmetry can be derived from coupling efficiency map by deconvolution. We build the mathematical model of the deconvolution method and recover the beam profile with simulated data. With proper modeling and data smoothing, the PSF of a FSO system is recovered with great consistency to the simulation data. The recovered profile can be used for guidance with the alignment of the system. Although the simulated data is rotationally symmetric, the deconvolution method can be improved in the future to be compatible with focal spot with arbitrary beam profile. The method can also be useful in applications such as laser beam profiling, online system testing, phase retrieval and so on.

Methods of creating a natural environment are increasingly used to reduce stress in the workplace and increase productivity. When an artificial visual environment is created, it is important that the degree of self-similarity of the images approximates the values characteristic of the natural environment. It should be noted that the degree of selfsimilarity of the visual environment that surrounds a person in everyday life (in an office, in an urban environment) is usually low, and natural landscapes have a high degree of self-similarity. A visual environment with a high degree of self-similarity can be obtained by passing laser radiation through optically inhomogeneous media or objects of complex shape with a small-sized chaotic structure. The images obtained in this way have a natural structure in a certain sense, because they are based on the effects of interference and dispersion (i.e. natural). However, in our experiments the resulting image has areas of great brightness. The eye adopts precisely for the perception of these parts of the image, and the most interesting part of its structure can be out of the range of perception, which denies the efforts to make such an image. We analyze possible ways of solving this problem and get a complex image of the structure without sharp changes in brightness. The main task here is to select the parameters of the complex object and the parameters of the laser beam so that the object can be made without using special microtechnologies and at the same time obtain the desired image.

MAORY (Multi-conjugate Adaptive Optics RelaY) will be the multi-conjugate adaptive optics module for the ELT first light. MAORY is a post focal relay optics and supports the MICADO imager and spectrograph. The tolerance process of MAORY is one of the most important step in the instrument design since it is intended to ensure that MAORY requested performances are satisfied when the final assembled instrument is operative. At the end, the assignment of tolerances to the various opto-mechanical parameters should be a trade-off between final cost of the system and its resulting performances. This paper describes the logic behind the tolerance analysis starting from definition of quantitative figures of merit for MAORY requirements and ending with estimation of MAORY performances perturbed by opto-mechanical tolerances. The method used to estimate tolerances takes care of compensation of errors during assembly/alignment procedure and uses a Root-Sum-Squared (RSS) merit function to combine independent error contributions. There are two requirements that limit the allowable changes of opto-mechanical parameters. The Root-Mean-Squared wavefront error (RMS WFE) and the optical distortion. The first one must satisfy diffraction limited performance over the MICADO Field-of-View (FoV) while the second one must satisfy high astrometric accuracy and precision. As criterion for tolerancing, the defined merit function considers the RMS wavefront referred to star centroids and adds boundary constraints on the compensators and geometric distortion in MICADO FoV. To evaluate the impact of tolerances on astrometry, a Monte Carlo approach was followed validating the expected performances from a pure opto-mechanical point of view.

A real-time vibration compensation control system based on fast-steering-mirrors(FSM) is demonstrated. The system compensates the dominant frequency of vibration spectrum. Fast Fourier transform (FFT) is mainly used as the control method. The simulative experiment on vibration compensation of satellite platform is proceeded. The results show that the highest effective compensational frequency can be improved to 80 Hz. Furthermore, this method has the superiority on bandwidth, tolerance and stability.

The field of application of aspheric optics is steadily expanding. Aspheric surfaces can be found in photographic optics, astronomical optics and other optical systems that are now at the forefront of the optical science. The production of elements with aspherical surfaces is a very long and time-consuming process both from the design and the technological points of view. In CAE-systems the information is placed in accordance with the developed dialog interface and the traditions of a country / programming language and others. These data are specific for each program, which greatly complicates the processing of data. The purpose of this work is to investigate the possibility to automate the production of design documentation for optical elements with aspherical surfaces in accordance with international ISO standards. It was decided to develop an application software package, embedded in the CAD-environment. The presented software package solves the problem of producing design documentation based on the data from such CAE-systems as OPAL PC and Zemax. The methodical material, developed during the research, contains information about work with parameters of aspherical surfaces in the CAE-systems indicated above. The design documentation must be complied in accordance with Russian standards and ISO 10110-12: 2007. Dialog windows of the software request all the data necessary for the release of drawings. The report presents different approaches of algorithmic solutions of the tasks, the dialog interface and examples of document automatic execution results.

An adjustable surface shape with a high accuracy attracts a significant interest in the development of X-ray optical elements. However, the optical parameters of the conventional polished mirror are fixed, lacking adaptability and leading to significantly limited application targets. Based on adaptive optics technology, the X-ray deformable mirror can be achieved using the bending principle of a piezoelectric bimorph. In this study, we developed an X-ray lead-zirconate-titanate-(PZT) deformable mirror with an adjustable surface shape. The X-ray deformable mirror was simulated and optimized using the ANSYS software to ensure the feasibility of the design scheme. An X-ray deformable mirror prototype was manufactured based on the simulation results. It had a simple structure consisting of a 400-μmthick D263 glass substrate and 500-μm-thick PZT thin sheet. The PZT thin sheet consisted of 11 element electrode actuators. We used a ZYGO interferometer for an on-line surface shape feedback of the X-ray deformable mirror. By changing the voltage loads of the actuators, the glass substrate surface shape could be adjusted, and a target cylinder with a radius of curvature of 30 m was obtained. The curvature radius of the target cylinder could be changed, from 5 m to infinity.

The problems of using stray light visualization for the effective analysis and design of complex optical systems are considered. Examples of real applications are given where the use of the light propagation criterion in conjunction with the visual representation of the ray path makes it possible to effectively analyze complex optical design problems. The suggested solution allows not only to visualize source of the stray light in the optical system but alto to render the image on the detector taking into account diffuse scattering on all illuminated surfaces.

Decreasing mass of telescope mirrors issue is still actual today. Common lightweighting mirrors method uses relief back structure. In the article it is proposed to change back flat surface to spherical one. Options of mirror design are considered: design of "negative" (with the smallest thickness in the center), "positive" (with the smallest thickness along the edge) meniscus and meniscus with the same thicknesses. The schemes of mounting such mirrors in telescope are considered.

A company that specifies optical systems with multiple assemblies has several procurement choices: Contract different sub-assemblies to multiple companies or find a single company that has the range of capabilities to complete all the optical systems. There are advantages to working with a company that has a large suite of capabilities and is vertically integrated. A vertically integrated optical system manufacturer can deliver on all parts of the optical system supply chain: optical material, optical and mechanical finishing, thin film coating, assembly, testing, and packaging. The benefit to working with a company that has capabilities in each of these areas is the knowledge and expertise of the individual process details and the understanding of the downstream impact of each process. This knowledge can lead to improved Design For Manufacturability (DFM) which can reduce the complexity, reduce cost of the end product, and ensure product performance. Obtaining maximum optical performance of multiple optical assemblies sourced from different suppliers can be a difficult task. Often the result is more challenging specifications on the individual assemblies to guarantee the performance of the entire system. This can lead to increased cost, complexity, and lead time. By using multiple suppliers, there are additional risks such as mechanical interface mismatch, optical performance failure, and stray light.

We present a lightweight mirror made of a magnesium alloy for applications to space-borne telescopes and optics in instruments. A non-flammable magnesium alloy was recently developed. We consider this alloy to be a promising material for a lightweight mirror due to its high stiffness, high fracture toughness, low density, and suitability for machining. First, small flat mirrors were fabricated to obtain and improve the fabrication conditions. Then, a 175-mm magnesium-alloy mirror, with a spherical mirror surface and a backside hexagonal cutout structure to reduce the mass of the mirror, was designed and fabricated. The spherical mirror surface was fabricated using a diamond-turning process. The evaluated residual of the surface figure of the 175-mm mirror from the design is 0.90 μm rms. The deformation caused by the jig used for the fabrication was one of the major factors that increased the residual of the surface figure. The surface roughness of the 175-mm mirror was evaluated, and values of Sa = 9.6 nm and Sq = 12.6 nm were obtained by averaging the data of four measurements with a 167 μm × 167 μm field of view. Methods to improve the mirror surface are discussed. We also discuss space-borne telescopes and instruments for which this magnesium alloy is one of promising materials.

In mobile devices, 3D Sensing is one of the latest functions. This can be achieved by Time-of-Flight (ToF) method or structured light method. Infrared structure light projector is composed of a laser light source, a collimated lens and a diffractive optics element (DOE). The light sources can be divided into two common types: the Edge Emitting Laser (EEL) or the Patterned Vertical Cavity Semiconductor Emission Laser Array (patterned-VCSEL array). In this paper, we will compare these two optical structures, EEL with high density dots pattern and patterned-VCSEL array with several impulse dots.

The aim of this contribution is to derive third-order aberration (Seidel) coefficients for a thick lens in air with arbitrary focal length. The explicit analytic dependence of individual aberration coefficients on a lens thickness will be presented. Such formulas make possible to analyze an influence of the lens thickness on lens aberration properties and the replacement of a thick lens optical system by a thin lens model. Equations are described for the re-calculation of aberration coefficients for a different value of focal length and a different value of entrance pupil position. The presented formulas have a fundamental importance for the optical design of optical systems consisting several thick lenses, because these formulas show the influence of the thickness of individual lenses on aberrations of the whole optical system. Furthermore, the thickness of individual lenses can be analytically calculated in order the lens had a required value of specific aberration. The designed optical system then may serve as an initial system for further optimization using optical design software.

Off-axis and eccentric pupil optical configurations are becoming more and more used in a variety of applications, in particular they are the most preferred solution for cameras devoted to study planetary surfaces, small solar system bodies (i.e. asteroids and comets) and also the atmospheres of the exoplanets. These optical designs, being devoid of central obstruction, are able to guarantee better PSF and MTF performance, and thus higher contrast imaging capabilities with respect to classical on-axis designs. In particular they are suitable for looking at extended targets with intrinsic low contrast features, or scenes where a high dynamic signal range is present. The tolerance analysis tools available in most of the commercial raytracing software packages are able to deal automatically with on-axis surfaces, but they have to be adapted for considering the off-axis cases. In particular, some tricks have to be considered in the definition of the off-axis surfaces to obtain the correct tolerance results when the way in which the surfaces are manufactured and/or mounted needs to be taken into account. For example, an off-axis section of a conic surface can be either obtained by cutting an off-axis piece from a large on-axis parent element or, as it is more common nowadays, by manufacturing it stand-alone. In this paper, a review of the tricks that the author has devised during her twenty-year experience in designing and tolerancing off-axis systems will be given. In particular the methods adopted to deal with the surface tolerance analysis of some off-axis instruments for space applications will be described in detail.

In this work, a ring resonator is designed with two rings for the sensing application. The waveguide is designed with 400nm wide and 180nm high. Both the rings are designed with 3.1μm radius each. The straight waveguide couples with the ring at 1550nm wavelength. The mode profiles and the spectrum of resonances are observed at mid- infrared wavelength, 1550nm. The measurements of the mode profile, refractive index and spectral properties of the design facilitate to monitor and modify the optical properties of the ring resonator structure. The phase shift in the resonance is observed, which can be implemented in the design of the sensor based ring resonator. In sensing applications the small size of ring resonator plays an important role, the interaction length of ring resonator with few tens of centimeters or even longer gives better sensing performance. Ring resonator offers enhanced light intensity near its surface with the enhancement being proportional to the Q-factor, which is due to the circulating nature of the resonant light. The coupling between the straight waveguide and the ring at 1550nm wavelength and is simulated using Lumerical FDTD. In optical sensors, a thin layer is attached to one of the ring surface, to observe the phase shift in the resonance. Since the refractive index of the thin layer on top of the ring structure is different from the surrounding medium which is typically water based, a change of index happens at the surface of the sensor which is measured for detecting the presence of additional layer in the cover medium. Hence the ring resonator structure can be implemented for bio-sensing application.

We present the current optical design of GMACS, a multi-object wide field optical spectrograph currently being developed for the Giant Magellan Telescope, a member of the emerging generation of Extremely Large Telescopes (ELTs). Optical spectrographs for ELTs have unique design challenges and issues. For example, the combination of the largest practical field of view and beam widths necessary to achieve the desired spectral resolutions force the design of seeing limited ELT optical spectrographs to include aspheric lenses, broadband dichroics, and volume phase holographic gratings - all necessarily very large. We here outline details of the collimator and camera subsystems, the design methodology and trade-off analyses used to develop the collimator subsystem, the individual and combined subsystem performances and the predicted tolerances.

The well-known Gerchberg-Saxton (GS) algorithm allows the reconstruction of an unknown wave front from known intensity distributions on a few planes of an optical system, for example, in the input plane and the focal plane. It is also the method of choice for the production of computer-generated holograms and calculation of the transmission function of diffractive optical elements (DOEs) generating so-called structured laser beams. Such ‘unconventional’ laser beams have unique features of an amplitude/phase/polarisation distribution, significantly extending opportunities for application of laser optics in many fields of modern science. Here, we propose a new modification of the basic GS algorithm that can be used to calculate a pure-phase transmission function of DOEs which generate complex intensity distributions with submicron features. DOEs designed in this way can be used in the field of laser fabrication of nano- and micropatterns, allowing the high-performance single-step fabrication of nanostructures for real applications in nanophotonics and optical manipulation.

Laser Doppler velocimetry (LDV) is one of the recent applied technologies in optical detection, and it has become an important research topic recently. In this research work, a previous developed Laser Doppler velocimetry system has been modified and applied to the tube flow rate measurement. We used optical fiber components as waveguides to make it easier to guide and focus the sampling light to tube flow. The scattered light was collected and coupled with the reference light to produce an interference beam. When the fluid flowed in the tube, the Doppler shift frequency according to the flow rate would exist in the interference beam. The Doppler shift frequency is calculated by using short-time Fourier transformation (STFT) algorithm to obtain the flows velocities. The tube flow contained the microparticles, therefore Mie scattering phenomena needed to be investigated. In the experiments, the 1 micron polystyrene suspension was used with a concentration of 1:50 and a peristaltic pump was used to pump the fluid flowing through the tube at the velocity of 5 mm/s, 10mm/s, 20mm/s, and 30 mm/s. The STFT algorithm programmed by matlab was used to acquire the spectrum and the variation of frequency. The measurement results confirmed that the particle flow rate has a linear relationship with the frequency of the STFT analysis. In this study, an LDV system has been established, which can measure the flow rate of tube particles by Doppler shift measurement and can be easily manipulated during the process.