Proceedings Volume 9889

Optical Modelling and Design IV

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Proceedings Volume 9889

Optical Modelling and Design IV

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Volume Details

Date Published: 25 July 2016
Contents: 10 Sessions, 72 Papers, 0 Presentations
Conference: SPIE Photonics Europe 2016
Volume Number: 9889

Table of Contents

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Table of Contents

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  • Front Matter: Volume 9889
  • Waveguides and Fibres
  • Theoretical Emphasis: Maxwell Solvers I
  • Theoretical Emphasis: Maxwell Solvers II
  • Imaging, Image Processing, and Aerial and Space Applications
  • Theoretical Emphasis: Polarisation and Holography
  • Design, Lighting, Sources
  • Experimental Emphasis and Medical Applications
  • Nonimaging and Freeform Optics
  • Poster Session
Front Matter: Volume 9889
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Front Matter: Volume 9889
This PDF file contains the front matter associated with SPIE Proceedings Volume 9889, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.
Waveguides and Fibres
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Simulation of bended planar waveguides for optical bus-couplers
Lukas Lorenz, Krzysztof Nieweglowski, Klaus-Jürgen Wolter, et al.
In our work an optical bus-coupler is proposed, which enables easy bidirectional connection between two waveguides without interrupting the bus using a core-to-core coupling principle. With bended waveguides the coupling ratio can be tuned by adjusting the overlap area of the two cores. In order to ensure large overlap areas at short coupling lengths, the waveguides have rectangular cross sections. To examine the feasibility of this coupling concept a simulation was performed, which is presented in this paper. Due to multimode waveguides, used in short range data communication, a non-sequential ray tracing simulation is reasonable.

Simulations revealed that the bending of the waveguide causes a redistribution of the energy within the core. Small radii push the main energy to the outer region of the core increasing the coupling efficiency. On the other hand, at excessive lowered bend radii additional losses occur (due to a coupling into the cladding), which is why an optimum has to be found. Based on the simulation results it is possible to derive requirements and design rules for the coupling element.
Shallow etch electrical isolation in capacitively loaded Mach-Zehnder modulators
To compensate for velocity mismatch in travelling wave opto-electronic devices, the microwave velocity of the propagating RF signal is reduced by introducing capacitively loaded elements. For high speed operation, these elements must be electrically isolated from one another, which is typically achieved by using ion-implantation to render the p-doped material non-conducting. We propose and demonstrate through optical and electrical simulations that ion-implantation can be avoided by using a quasi-shallow etch to electrically isolate the capacitive elements. High isolation can be achieved using such an etch without introducing additional losses to the propagating optical signal.
Theoretical Emphasis: Maxwell Solvers I
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Analysis of all-optically tunable functionalities in subwavelength periodic structures by the Fourier modal method
Subhajit Bej, Jani Tervo, Jorge Francés, et al.
We propose the nonlinear Fourier Modal Method (FMM) [J. Opt. Soc. Am. B 31, 2371 (2014)] as a convenient and versatile numerical tool for the design and analysis of grating based next generation all-optical devices. Here, we include several numerical examples where the FMM is used to simulate all-optically tunable functionalities in sub-wavelength periodic structures. At first, we numerically investigate a 1-D periodic nonlinear binary grating with amorphous TiO2. We plot the diffraction efficiency in the transmitted orders against the structure depth for normally incident plane wave. Change in diffraction efficiencies for different incident field amplitudes are evident from the plots. We verify the accuracy of our implementation by comparing our results with the results obtained with the nonlinear Split Field-Finite Difference Time Domain (SF-FDTD) method. Next we repeat the same experiment with vertically standing amorphous Titanium dioxide (TiO2) nanowire arrays grown on top of quartz which are periodic in two mutually perpendicular directions and examine the efficiencies in the direct transmitted light for different incident field amplitudes. Our third example includes analysis of a form birefringent linear grating with Kerr medium. With FMM we demonstrate that the birefringence of such a structure can be tuned by all-optical means. As a final example, we design a narrow band Guided Mode Resonance Filter (GMRF). Numerical experiments based on the nonlinear FMM reveal that the spectral tunability of such a filter can be obtained by all-optical means.
Efficient split field FDTD analysis of third-order nonlinear materials in two-dimensionally periodic media
Jorge Francés, Sergio Bleda, Subhajit Bej, et al.
In this work the split-field finite-difference time-domain method (SF-FDTD) has been extended for the analysis of two-dimensionally periodic structures with third-order nonlinear media. The accuracy of the method is verified by comparisons with the nonlinear Fourier Modal Method (FMM). Once the formalism has been validated, examples of one- and two-dimensional nonlinear gratings are analysed. Regarding the 2D case, the shifting in resonant waveguides is corroborated. Here, not only the scalar Kerr effect is considered, the tensorial nature of the third-order nonlinear susceptibility is also included. The consideration of nonlinear materials in this kind of devices permits to design tunable devices such as variable band filters. However, the third-order nonlinear susceptibility is usually small and high intensities are needed in order to trigger the nonlinear effect. Here, a one-dimensional CBG is analysed in both linear and nonlinear regime and the shifting of the resonance peaks in both TE and TM are achieved numerically. The application of a numerical method based on the finite- difference time-domain method permits to analyse this issue from the time domain, thus bistability curves are also computed by means of the numerical method. These curves show how the nonlinear effect modifies the properties of the structure as a function of variable input pump field. When taking the nonlinear behaviour into account, the estimation of the electric field components becomes more challenging. In this paper, we present a set of acceleration strategies based on parallel software and hardware solutions.
Theoretical Emphasis: Maxwell Solvers II
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Fully vectorial simulation of light propagation through uniaxial and biaxial crystals
Nowadays, to achieve high accuracy in optical measurements, manufacturing and particle trap- ping, light { many of its aspects and especially the polarization - must be controlled precisely. Uniaxial and biaxial crystals, due to their birefringent properties, are probably the most suitable choices for manipulating light in a vectorial manner. For a better understanding and design of optical systems which include birefringent crystals, a fully vectorial simulation technique is needed. Several approaches have been put forward, but very often, they are restricted to either certain types of crystals or certain types of fields and solve the problems only in specific cases. We present, based on Berreman's 4x4 matrix formulation, a numerical simulation technique for the propagation of general fields through any uniaxial or biaxial crystal. With this technique, we demonstrate simulation examples including the generation of optical vortices with uniaxial crystals, the formation of configurable optical bottle beams with biaxial crystals, and so on. In addition, we also briefly introduce the simulation technique for the possible second-order nonlinear effects taking place in birefringent materials.
Analysis of the effect of stress-induced waviness in airgap-based optical filters
The preliminary results of a study on the effect of the membrane deformation on the optical response of the distributed Bragg reflector, that is based on a stack of such membranes, are presented. The analysis is applied to airgap-based optical filters, which offer an enhanced refractive index contrast and hence are highly promising for optical MEMS devices. The available methods and materials in MEMS technology would make fabrication of such devices feasible, but the optical requirements impose strict geometrical implications on the membrane structure. Although (an overall) tensile stress in membrane is expected to result in a flat structure after the release, a stress gradient results in a deformed structure. A combined finite element and finite-difference time- domain method has been utilized in this work to study the effects of a stress gradient in a distributed Bragg reflector. The results on the effects of both a linear and a non-linear stress gradient are presented. It is shown that a non-linear stress profile results in twice the deformation and a further reduction of optical performance.
Solution of the wave equation for an oscillating punctual source by means of the finite elements method
Finite Elements Method (FEM) and Finite Difference Method (FDM) in the Euler implicit approach, were used in order to determine the bi-dimensional electromagnetic field. of an oscillating punctual source inside a square geometry with three reflective boundaries and an absorbing one. Although the main approach consist in solving the wave equation for the electric field., it was decided to use the approach of electromagnetic potentials V and A because those potentials give a simpler solution for both, the electric and magnetic field. Besides, a comparison with theory was made, solving for an electromagnetic field without boundaries produced by an oscillating punctual source.
Scattering of a focused laser beam by a cluster of axisymmetric shaped microparticles
Scattering of an arbitrarily focused electromagnetic Gaussian beam by a cluster consisting of a chain of axisymmetric microparticles is presented. The illustrated technique in this work combines the plane-waves spectrum method and a modification of the cluster T-matrix method. This combination provides a powerful tool to calculate the scattered fields from a cluster of different shaped particles illuminated with an arbitrarily incident electromagnetic wave. The presented technique is used to calculate the scattering matrix elements of different cases of a cluster illuminated with different beam focusing.
Imaging, Image Processing, and Aerial and Space Applications
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Design of Excess 3 to BCD code converter using electro-optic effect of Mach-Zehnder Interferometers for efficient data transmission
Santosh Kumar, Chanderkanta , Angela Amphawan
Excess 3 code is one of the most important codes used for efficient data storage and transmission. It is a non-weighted code and also known as self complimenting code. In this paper, a four bit optical Excess 3 to BCD code converter is proposed using electro-optic effect inside lithium-niobate based Mach-Zehnder interferometers (MZIs). The MZI structures have powerful capability to switching an optical input signal to a desired output port. The paper constitutes a mathematical description of the proposed device and thereafter simulation using MATLAB. The study is verified using beam propagation method (BPM).
Design and implementation of flexible laboratory system for beam propagation study through weak atmospheric turbulence
Different applications such as astronomy, remote optical sensing and free space optical communications, among others, require both numerical and laboratory experimental simulations of beam propagation through turbulent atmosphere prior to an outdoor test. While rotating phase plates or hot chambers can be applied to such studies, they do not allow changing the atmospheric conditions and the propagation distance in situ. In contrast, the spatial light modulators (SLMs) are a flexible alternative for experimental turbulence simulation. In this work we consider an experimental setup comprising two SLMs for studying laser beam propagation in weak atmospheric turbulence. The changes of atmospheric conditions and propagation distances are properly achieved by the adjustment of the phase screens and the focal distances of digital lenses implemented in both SLMs. The proposed system can be completely automatized and all its elements are in fixed positions avoiding mechanical misalignment. Its design, propagation distance and atmospheric condition adjustment are provided. The setup performance is verified by numerical simulation of Gaussian beam propagation in the weak turbulence regime. The obtained parameters: scintillation index, beam wander and spreading are compared to their theoretical counterparts for different propagation distances and atmospheric conditions.
Design of 4 to 2 line encoder using lithium niobate based Mach Zehnder Interferometers for high speed communication
Amrindra Pal, Santosh Kumar, Sandeep Sharma, et al.
Encoder is a device that allows placing digital information from many inputs to many outputs. Any application of combinational logic circuit can be implemented by using encoder and external gates. In this paper, 4 to 2 line encoder is proposed using electro-optic effect inside lithium-niobate based Mach-Zehnder interferometers (MZIs). The MZI structures have powerful capability to switching an optical input signal to a desired output port. The paper constitutes a mathematical description of the proposed device and thereafter simulation using MATLAB. The study is verified using beam propagation method (BPM).
Spatial frequency characterisation of a far-field superlens to facilitate general purpose imaging
Farzaneh Fadakar Masouleh, Paul Teal, Ciaran Moore
Based on sub-wavelength energy concentration and enhancement of evanescent fields, far-field super-lenses (FSLs) were proposed recently as a means to achieve super-resolution imaging and thus improve the accuracy and resolution of optical microscopy. Comprised of a thin-film plasmonic enhancement layer and a diffraction grating, the performance of FSLs depends greatly on the geometry and size of its constituent parts. In this paper, we aim to characterize the resolution capabilities of FSLs in a novel and meaningful way, while also exploring the effects of non-ideal grating geometries due to fabrication limitations on imaging performance. We use finite element modelling to explore trapezoidal, inverse-trapezoidal, circular, rounded rectangular, and rectangular grating profiles and present a transfer function that quantifies the performance of these grating profiles in terms of their transmission at different wavenumbers.
Theoretical Emphasis: Polarisation and Holography
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α-bandlimited diffuser in fractional Fourier optics
Alberto Patiño-Vanegas, Pierre-Emmanuel Durand, Rafael Torres, et al.
We propose a method for calculating appropriate α-band limited diffusers using the fractional Fourier transform. In order to do this, we implement a method for performing a numerical interpolation in the fractional Fourier domain. Such diffusers with compact support in the Fresnel regime may be used in fractional Fourier optical systems where the use of diffusers produce speckles, e.g. digital holography or optical encryption. Numerical simulations are presented.
Design, Lighting, Sources
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Design and applications of a phase space analyzer
Denise Rausch, Alois Herkommer
In the last few years the requirement of more special and complex optical system increases as the demand in industries for higher efficiency increases. To satisfy the demand more complex optical elements substitute continuously standard components. Therefore it is of high interest to develop new methods in evaluating optical systems. In classical illumination design a huge number of rays has to be traced to get enough information to evaluate the performance of the system. An other method is to investigate the transport of etendue in the phase space picture where we have direct access to the radiance, irradiance and radiant intensity without extensive ray tracing. The phase space analyzer offers a different way to illustrate directly the phase space diagram of an arbitrary light distribution restricted to two dimensions. This method is much faster than traditional ray tracing. Most often used illumination components like integrator rods and optical arrays can be understood in the phase space approach.
Evaluation of simulation alternatives for the brute-force ray-tracing approach used in backlight design
Karel Desnijder, Peter Hanselaer, Youri Meuret
A key requirement to obtain a uniform luminance for a side-lit LED backlight is the optimised spatial pattern of structures on the light guide that extract the light. The generation of such a scatter pattern is usually performed by applying an iterative approach. In each iteration, the luminance distribution of the backlight with a particular scatter pattern is analysed. This is typically performed with a brute-force ray-tracing algorithm, although this approach results in a time-consuming optimisation process. In this study, the Adding-Doubling method is explored as an alternative way for evaluating the luminance of a backlight. Due to the similarities between light propagating in a backlight with extraction structures and light scattering in a cloud of light scatterers, the Adding-Doubling method which is used to model the latter could also be used to model the light distribution in a backlight. The backlight problem is translated to a form upon which the Adding-Doubling method is directly applicable. The calculated luminance for a simple uniform extraction pattern with the Adding-Doubling method matches the luminance generated by a commercial raytracer very well. Although successful, no clear computational advantage over ray tracers is realised. However, the dynamics of light propagation in a light guide as used the Adding-Doubling method, also allow to enhance the efficiency of brute-force ray-tracing algorithms. The performance of this enhanced ray-tracing approach for the simulation of backlights is also evaluated against a typical brute-force ray-tracing approach.
Opto-thermal study of cooling strategies for high-luminance white-light solid-state sources
António Correia, Peter Hanselaer, Youri Meuret
Solid-state sources have become ubiquitous is many lighting applications. For general lighting, phosphors are typically employed to produce white light from the narrowband light emitted from solid-state sources. As the optical output power from solid-state sources keeps increasing, increasingly higher luminance can be obtained, which, unfortunately, also increases the phosphor's temperature. These materials' colour conversion potential, encoded by the quantum yield, has complex dependencies with temperature. To obtain an accurate assessment of the performance of a high-luminance white light source configuration based on individual solid-state sources, it is imperative to accurately model the temperature distribution inside the phosphor material and consider the effect of temperature on the quantum yield of the phosphor. In addition, the feedback of the varying quantum yield on the generated heat inside the phosphor should also be considered. An opto-thermal framework has been previously proposed to accurately simulate the opto-thermal effects in phosphors when designing lighting systems. In this paper, this framework is applied to a novel optical configuration to investigate thermal bottlenecks and test cooling strategies to avoid them. For the specific configuration tested, using an active cooling strategy and concentrating the laser light on the phosphor region with the best thermal dissipation proved to be the best solutions.
Optical design of a high-power LED-based solar simulator
Veronica Toro-Betancur, Alejandro Velásquez-López, David Velásquez, et al.
The optical design of a High-Power LED based Solar Simulator was made in order to reach the AM1.5G spectrum standards. An optical model of the light emitted by the LEDs was made and used for spectral intensities calculations and the light intensity uniformity was optimized. A class AAA solar simulator was designed using a hexagonal LED distribution.
Optical systems modeling and experimental realization of pump and probe technique: investigation of nonlinear absorption in colloidal quantum dots
Two optical systems modeling of laser and broadband radiation focusing, that is necessary for realization of the pump and probe method, was carried out in this work. Modeling was utilized to construct experimental setup for transmission spectra measuring of studied sample by probe nanosecond broadband radiation (coumarin photoluminescence) depending on the intensity of the nanosecond laser pump pulses. The saturation effect of absorption and the induced charge Stark-effect coexistence and predominate issue of these effects are determined by power of optical excitation. In dependence of tuning of excitation radiation frequency from basic exciton transition frequency nonlinear effects in colloidal CdSe/ZnS quantum dots has been investigated.
Experimental Emphasis and Medical Applications
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Design of a miniaturized integrated spectrometer for spectral tissue sensing
Minimally-invasive image-guided procedures become increasingly used by physicians to obtain real-time characterization feedback from the tissue at the tip of their interventional device (needle, catheter, endoscopic or laparoscopic probes, etc…) which can significantly improve the outcome of diagnosis and treatment, and ultimately reduce cost of the medical treatment. Spectral tissue sensing using compact photonic probes has the potential to be a valuable tool for screening and diagnostic purposes, e.g. for discriminating between healthy and tumorous tissue. However, this technique requires a low-cost broadband miniature spectrometer so that it is commercially viable for screening at point-of-care locations such as physicians’ offices and outpatient centers. Our goal is therefore to develop a miniaturized spectrometer based on diffractive optics that combines the functionalities of a visible/near-infrared (VIS/NIR) and shortwave-infrared (SWIR) spectrometer in one very compact housing. A second goal is that the hardware can be produced in high volume at low cost without expensive time consuming alignment and calibration steps. We have designed a miniaturized spectrometer which operates both in the visible/near-infrared and shortwave-infrared wavelength regions ranging from 400 nm to 1700 nm. The visible/near-infrared part of the spectrometer is designed for wavelengths from 400 nm to 800 nm whereas the shortwave-infrared segment ranges from 850 nm to 1700 nm. The spectrometer has a resolution of 6 nm in the visible/near-infrared wavelength region and 10 nm in the shortwave-infrared. The minimum SNR of the spectrometer for the intended application is about 151 in the VIS/NIR range and 6000 for SWIR. In this paper, the modelling and design, and power budget analysis of the miniaturized spectrometer are presented. Our work opens a door for future affordable micro- spectrometers which can be integrated with smartphones and tablets, and used for point-of-care applications. As next steps in the development, we will manufacture the different optical components and experimentally characterize the spectrometer device in more detail.
An improved approach for process monitoring in laser material processing
Hans-Georg König, Oliver Pütsch, Jochen Stollenwerk, et al.
Process monitoring is used in many different laser material processes due to the demand for reliable and stable processes. Among different methods, on-axis process monitoring offers multiple advantages.

To observe a laser material process it is unavoidable to choose a wavelength for observation that is different to the one used for material processing, otherwise the light of the processing laser would outshine the picture of the process. By choosing a different wavelength, lateral chromatic aberration occurs in not chromatically corrected optical systems with optical scanning units and f-Theta lenses. These aberrations lead to a truncated image of the process on the camera or the pyrometer, respectively. This is the reason for adulterated measurements and non-satisfying images of the process.

A new approach for solving the problem of field dependent lateral chromatic aberration in process monitoring is presented. Therefore, the scanner-based optical system is reproduced in a simulation environment, to predict the occurring lateral chromatic aberrations. In addition, a second deflecting system is integrated into the system. By using simulation, a predictive control is designed that uses the additional deflecting system to introduce reverse lateral deviations in order to compensate the lateral effect of chromatic aberration.

This paper illustrates the concept and the implementation of the predictive control, which is used to eliminate lateral chromatic aberrations in process monitoring, the simulation on which the system is based the optical system as well as the control concept.
Spot phosphor concept applied to the remote phosphor configuration of a white phosphor-converted LED
Paula Acuña, António Correia, Jana Ryckaert, et al.
Although the remote phosphor technology outperforms the conformal phosphor technology for mid-power applications, one of the limiting factors is the amount of phosphor required and its impact on the total cost. Besides, an important loss mechanisms in remote phosphor LED technology is the re-absorption of converted light. An obvious solution to this issue is enabling a light path for the converted light, such that further interactions with the phosphor element are avoided. In order to explore such a configuration, a simulation model of a phosphor element is devised and validated based on experimental data and the application of the inverse adding-doubling method. The resulting configuration, denoted as spot concept, along with a long-pass filter is shown to be a potential solution to reduce the phosphor usage. Since the moderate change in the light extraction ratio when applying the spot concept is partly attributed to the losses in the secondary optics needed to narrow the LED beam, the application of the spot concept configuration with a directional light source such as a laser diode could be a powerful combination for the enhancement of the light extraction ratio.
The application of diffractive optical elements in the optical coherence tomography
The article investigates the possibility of using diffractive optical elements on an example of the kinoform in the optical coherence tomography (OCT). The article gives a brief overview of modern methods of research in the OCT, the expediency of development hyperchromatic lenses for spectral OCT systems. The authors made the aberration analysis of diffractive optical element (DOE), conducted a review of its application, and the DOE proposed to use in the example of a kinoform as the main force component of the hyperchromatic lens. In conclusion, the article provides examples of developed hybrid lenses for two spectral ranges, lens transmittance analysis and the assessment of their adaptability.
Nonimaging and Freeform Optics
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Design of compact freeform LED flashlight capable of two different light distributions
Annie Shalom Isaac, Cornelius Neumann
Free-form optical surfaces are designed for desired intensity requirements for applications ranging from general to automotive lighting. But a single compact free-form optics which satisfies two different intensity distributions is not presented so far. In this work, a compact LED flashlight fulfilling two different intensity requirements that could be used in potentially explosive atmospheres is designed and validated. The first target is selected after a study on visibility analysis in fog, dust, and smoke environments. Studies showed that a ring-like distribution (5°- 10°) have better visual recognition for short distances in smoky environments. The second target is selected to have a maximum intensity at the peak to provide visibility for longer distances. We realized these two different intensity requirements by moving the LED with respect to the optics along the optical axis. To fulfill the above- required intensity distributions, hybrid TIR optics was designed as free-form curves calculated by combining several geometric optic methods. We validated the free-form TIR hybrid optics using Monte Carlo ray trace simulation. The overall diameter of the optics is 29 mm and 10 mm in thickness. The simulated results showed an optical efficiency of about 84% to realize both target light distributions in a single optics. Then we designed a whole flashlight consisting of LED, PMMA hybrid optics, PC glass casing and a housing including the critical thermal management for explosive environments. To validate the results, a prototype for the designed optics was made. The measured results showed an overall agreement with the simulated results.
Freeform optical design of an XY-zoom beam expander
Laser sources have become indispensable for industrial materials processing applications. These applications are accompanied with a variety of different demands and requirements on the delivered laser irradiance distributions. With a high spatial uniformity, top-hat beams provide benefits for applications like surface heat treatment or welding, in which it is desirable to uniformly illuminate a target surface. Some applications might not only favor a specific beam irradiance distribution but can benefit additionally from time-varying distributions. In this work, we present the analytic design of an XY-zoom beam expander based on movable freeform optics that allows to simultaneously vary the magnification in x- and y-direction, respectively. This optical functionality is not new; what is new is the idea that axially moving freeform lenses are used to achieve such an optical functionality by optimally exploiting the additional degrees of freedom that freeform surfaces offer. The developed analytic solution is fully described by very few initial parameters and does allow an increasingly accurate calculation of four freeform lenses described by high order XY Taylor polynomial surfaces. Moreover, this solution approach can be adapted to cope with additional optical surfaces and/or lens groups to further enhance the overall optical performance. In comparison with (existing) combinations of rotated cylindrically symmetric zoom beam expanders, such a freeform system consists of less optical elements and provides a much more compact solution, yet achieving excellent overall optical performance throughout the full range of zoom positions.
Direct design of two freeform optical surfaces for wide field of view line imaging applications
In this paper, we propose a multi-fields direct design method aiming to calculate two freeform surfaces with an entrance pupil incorporated for wide field of view on-axis line imaging applications. Both infinite and finite conjugate objectives can be designed with this approach. Since a wide angle imaging system requires more than few discrete perfect imaging points, the multi-fields design approach is based on partial coupling of multiple fields, which guarantees a much more balanced imaging performance over the full field of view. The optical path lengths (OPLs) and image points of numerous off-axis fields are calculated during the procedure, thus very few initial parameters are needed. The procedure to calculate such a freeform lens is explained in detail. We have designed an exemplary monochromatic single lens to demonstrate the functionality of the design method. A rotationally symmetric counterpart following the same specifications is compared in terms of RMS spot radius to demonstrate the clear benefit that freeform lens brings to on-axis line imaging systems. In addition, a practical achromatic wide angle objective is designed by combining our multi-fields design method with classic optical design strategies, serving as a very good starting point for further optimization in a commercial optical design program. The results from the perspective of aberrations plots and MTF values show a very good and well balanced performance over the full field of view.
Design of focal beam shaping system through irradiance and phase control
Focal beam shaping (FBS), or laser beam shaping at focus, is required in many laser applications. The most common approach is to use a phase element and a Fourier transform lens to generate at the focal plane of the lens the desired irradiance pattern, usually a at-top. The shaping quality depends strongly on a dimensionless parameter β. In case of long focal length and/or small focal spot, the input laser beam should be sufficiently large in order to get a large β value for a satisfying shaping quality. Therefore additional beam expansions might be needed. In this work, we propose a different approach with two plano-aspheric lenses that allows to control both irradiance and phase at focus. The two lenses are designed by an extended ray mapping technique combined with a rigorous backward wave propagation method, so that diffraction effects around laser focus can be implemented in a reliable way. With the developed approach, the shaping quality is guaranteed without the possible need for extra beam expanders, which makes the system more compact. The advantage of our design approach is demonstrated in direct comparison with the conventional Fourier approach for the same design example to transform a Gaussian beam to have a circular flat-top irradiance pattern.
Smart freeform optics solution for an extremely thin direct-lit application
Claude Leiner, Wolfgang Nemitz, Susanne Schweitzer, et al.
Light-emitting diodes (LEDs) based lighting solutions offer many advantages like the huge potential for energy saving, long lifetime, high reliability and the compact size compared to incandescent light bulbs. Especially the last-mentioned aspect favors new concepts for the design and integration of light points and luminaires. In case of a direct-lit system for general lighting applications the LEDs are separated by a certain distance, arranged in a regular array and illuminate an out-coupling surface which is placed in a certain height above the LED array. One approach to fulfill the demand of a uniform luminance of the out-coupling surface is to replace the surface by a diffuser sheet. In order to allow for a flat luminaire design the distance of the out-coupling surface has to be modified synchronously with a variation of the distance between the LEDs. This means, in order to maintain the uniformity of the luminance the distance to height ratio (DHR) of the optical arrangement has to be kept constant. A (from the viewpoint of costs desirable) reduction of the number of the LEDs and as a consequence thereof an increase of the DHR value can be achieved by using additional optical elements like, e.g., freeform optics. However, this can cause additional design problems due to the size of such optical elements.

In this contribution we discuss a smart design of an extremely flat direct-lit luminaire for general lighting applications. The main advantage of this concept is the increased DHR ratio compared to diffuser sheet only-approaches and a smaller thickness of the whole set-up compared to common freeform approaches. For this demand we have designed very thin freeform optical elements with a maximal height of 75 μm that allow to maintain a uniform illumination in direct-lit applications using an LED-array with a comparably large distance between the individual LEDs. The presented design concept in addition emphasizes the use of cost-effective manufacturing methods like grey scale laser lithography for mastering and roll-to-roll processing for large area manufacturing of these optical elements.
Blue-sensitized nanoparticle-(thiol-ene) polymer composites for volume holographic recording
We describe an experimental investigation of volume holographic recording in photopolymerizable thiol-ene based nanoparticle-polymer composites (NPCs) at a wavelength of 404 nm. We introduce a new photoinitiator, Irgacure819, for efficient volume holographic recording in the blue-violet spectral region and measure the photopolymerization dynamics and the holographic recording properties at its varying concentrations. It is found that doping of 0.1 wt.% Irgacure 819 provides the saturated refractive index modulation amplitude as large as 9.5×10−3 and the material recording sensitiviey as high as 1800 cm/J. These measured values are much larger than the minimum required values for holographic data storage media. It is also shown that the out-of-plane shrinkage can be suppressed more with decreasing the photoinitiator concentration. We compare these results with another blue sensitizer, Darocur TPO, to evaluate the performance of Irgacure 819.
Poster Session
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Design the algorithm compensation of vignetting error at optical-electronic autoreflection system by modelling vignetted image
Igor A. Konyakhin, Aiganym M. Sakhariyanova, Renpu Li
Nowadays one of metrology problems is the measurement of angular values, in particular, angular deformations in the critical points of oversized objects. For the solution of this problem, effectively use optoelectronic autoreflection systems. The autoreflection systems allows measuring a mirror turning angle as sensitive element in a point of angular deformation with a potential accuracy up to 0.05". Actually the error can exceed considerably the specified value because of existence of systematic error, one of which main components is the error flowing to vignetting of a working beam. The component of systematic error due to vignetting of the beam can be eliminated in case of existence of the analytical description of changes in irradiance distribution of the analyzed image. Because of the complexity of the analytical description of the vignetting processes proposes the use of computer models. Based on the received dependence for compensation of systematic error due to vignetting is equal D=30 arcsecs. As this systematic measurement error unacceptably large, there is a need to compensate for this error. For the design of the algorithm compensate for systematic error were considered three cases of displacement vignetting field on a matrix analyzer due to the rotation of control element. Using the compensation algorithm, the error due to the vignetting amounts to a negligible value 0.4 arcsecs. The designed algorithm compensation systematic error due to vignetting allows to increase the working distance at the autoreflection measurements.
Optical-electronic system controlling the position of a railway track with the help of reference marks
Margarita A. Shavrygina, Igor A. Konyakhin, Aleksandr N. Timofeev, et al.
Rail transport is the largest rail network worldwide. If you compare the number of passengers and of goods transported by different modes of transport, it appears that the share of rail transport represents a very tangible part of them. Ensuring a high level of rail safety is currently one of the primary tasks of States and organizations involved in rail. In order to contain a railway and to provide its performance, you must ensure a high quality of the Railway, so the establishment of systems to control the position of the path is relevant, especially in the field of optical-electronic instrument making. The purpose of work is development and research of optical-electronic system for controlling the position of a railway track with the help of reference marks.
Efficient formalism for treating tapered structures using the Fourier modal method
Andreas Dyhl Osterkryger, Niels Gregersen
We investigate the development of the mode occupations in tapered structures using the Fourier modal method. In order to use the Fourier modal method, tapered structures are divided into layers of uniform refractive index in the propagation direction and the optical modes are found within each layer. This is not very efficient and in this proceeding we take the first steps towards a more efficient formalism for treating tapered structures using the Fourier modal method. We show that the coupling coefficients through the structure are slowly varying and that only the first few modes are occupied. We exploit both of these properties in the developing of a more efficient formalism.
Cylindrical diffractive lenses recorded on PVA/AA photopolymers
Photopolymers are optical recording materials appealing for many different applications such as holography, data storage, interconnectors, solar concentrations, or wave-guides fabrication. Recently the capacity of photopolymers to record diffractive optical elements (DOE’s) has been investigated. Different authors have reported proposes to record DOE like fork gratings, photonics structures, lenses, sinusoidal, blazed or fork gratings. In these experiments there are different experimental set-ups and different photopolymers. In this work due to the improvement in the spatial light modulation technology together with the photopolymer science we propose a recording experimental system of DOE using a Liquid Cristal based on Silicon (LCoS) display as a master to store complex DOE like cylindrical lenses. This technology permits us an accurate control of the phase and the amplitude of the recording beam, with a very small pixel size. The main advantage of this display is that permit us to modify the DOE automatically, we use the software of the LCoS to send the voltage to each pixel In this work we use a photopolymer composed by acrylamide (AA) as polymerizable monomer and polyvinyl alcohol (PVA). We use a coverplated and index matched photopolymer to avoid the influence of the thickness variation on the transmitted light. In order to reproduce the material behaviour during polymerization, we have designed our model to simulate cylindrical lenses and used Fresnel propagation to simulate the light propagation through the DOE and analyze the focal plane and the properties of the recorded lenses.
Research of the long-focus Maksutov telephoto lens
The article presents the research result and the optical design of long-focus telephoto lens for photo shooting by the academician Maksutov’s scheme. It shows a review of lenses for photo shooting on the market today, and also an analysis of the correctional possibilities which is based on the scheme is presented; studied long-focus telephoto lens is compared with its closest analog, the calculation of a new telephoto lens with higher image quality is made on the basis of that comparison.
Simulation and optimization of faceted structure for illumination
Lihong Liu, Thierry Engel, Manuel Flury
The re-direction of incoherent light using a surface containing only facets with specific angular values is proposed. A new photometric approach is adopted since the size of each facet is large in comparison with the wavelength. A reflective configuration is employed to avoid the dispersion problems of materials. The irradiance distribution of the reflected beam is determined by the angular position of each facet. In order to obtain the specific irradiance distribution, the angular position of each facet is optimized using Zemax OpticStudio 15 software.

A detector is placed in the direction which is perpendicular to the reflected beam. According to the incoherent irradiance distribution on the detector, a merit function needs to be defined to pilot the optimization process. The two dimensional angular position of each facet is defined as a variable which is optimized within a specified varying range. Because the merit function needs to be updated, a macro program is carried out to update this function within Zemax. In order to reduce the complexity of the manual operation, an automatic optimization approach is established. Zemax is in charge of performing the optimization task and sending back the irradiance data to Matlab for further analysis.

Several simulation results are given for the verification of the optimization method. The simulation results are compared to those obtained with the LightTools software in order to verify our optimization method.
Power calculation of linear and angular incremental encoders
Aleksandr V. Prokofev, Aleksandr N. Timofeev, Sergey V. Mednikov, et al.
Automation technology is constantly expanding its role in improving the efficiency of manufacturing and testing processes in all branches of industry. More than ever before, the mechanical movements of linear slides, rotary tables, robot arms, actuators, etc. are numerically controlled. Linear and angular incremental photoelectric encoders measure mechanical motion and transmit the measured values back to the control unit. The capabilities of these systems are undergoing continual development in terms of their resolution, accuracy and reliability, their measuring ranges, and maximum speeds. This article discusses the method of power calculation of linear and angular incremental photoelectric encoders, to find the optimum parameters for its components, such as light emitters, photo-detectors, linear and angular scales, optical components etc. It analyzes methods and devices that permit high resolutions in the order of 0.001 mm or 0.001°, as well as large measuring lengths of over 100 mm. In linear and angular incremental photoelectric encoders optical beam is usually formulated by a condenser lens passes through the measuring unit changes its value depending on the movement of a scanning head or measuring raster. Past light beam is converting into an electrical signal by the photo-detecter’s block for processing in the electrical block. Therefore, for calculating the energy source is a value of the desired value of the optical signal at the input of the photo-detecter’s block, which reliably recorded and processed in the electronic unit of linear and angular incremental optoelectronic encoders. Automation technology is constantly expanding its role in improving the efficiency of manufacturing and testing processes in all branches of industry. More than ever before, the mechanical movements of linear slides, rotary tables, robot arms, actuators, etc. are numerically controlled. Linear and angular incremental photoelectric encoders measure mechanical motion and transmit the measured values back to the control unit. The capabilities of these systems are undergoing continual development in terms of their resolution, accuracy and reliability, their measuring ranges, and maximum speeds. This article discusses the method of power calculation of linear and angular incremental photoelectric encoders, to find the optimum parameters for its components, such as light emitters, photo-detectors, linear and angular scales, optical components etc. It analyzes methods and devices that permit high resolutions in the order of 0.001 mm or 0.001°, as well as large measuring lengths of over 100 mm. In linear and angular incremental photoelectric encoders optical beam is usually formulated by a condenser lens passes through the measuring unit changes its value depending on the movement of a scanning head or measuring raster. Past light beam is converting into an electrical signal by the photo-detecter’s block for processing in the electrical block. Therefore, for calculating the energy source is a value of the desired value of the optical signal at the input of the photo-detecter’s block, which reliably recorded and processed in the electronic unit of linear and angular incremental optoelectronic encoders.
Optical wave beam propagation in two-lens scheme with arbitrary parameters
Two-lens optical scheme as a system of the optical information processing and transmission is considered. On the basis of applying radio-optics methods, the theory of linear systems and system approach a mathematical model describing the transformation of the optical wave beam in this system is proposed. Input-output ratio of the system in the form of a general spatial impulse response of all linear units included in the system is established.

The problem of energy losses of the optical radiation in such a system is considered. As the input and output of system of the single-mode optical fiber is used. The equations defining the minimum possible level of energy losses caused by the diffraction of beam is obtained. The analysis showed that the losses depend explicitly on several parameters: the radiation wavelength, the distance between the end of fiber and the aperture, and the ratio of the diameter of fiber and lens aperture. With the help of computer simulation in Matlab system the losses depending on the parameters mentioned above is presented.
Optimized design of high-order series coupled Yb3+/Er3+ co-doped phosphate glass microring resonator filters
The optimized geometry based on high-order active microring resonators (MRR) geometry is proposed. The solution possesses both the filtering and amplifying functions for the signal at around 1534nm (pump 976 nm). The cross-grid resonator with laterally, series-coupled triple-microrings, having 15.35μm radius, in a co-propagation topology between signal and pump, is the structure under analysis (commonly termed an add-drop filter).
The model of the optical-electronic control system of vehicles location at level crossing
Level crossing – one of the most dangerous sections of the road network, where railway line crosses motor road at the same level. The collision of trains with vehicles at a level crossing is a serious type of road traffic accidents. The purpose of this research is to develop complex optical electronic control system of vehicles location in the dangerous zone of level crossing. The system consists of registration blocks (including photodetector, lens, infrared emitting diode), determinant devices and camera installed within the boundaries of level crossing. The system performs detection of objects (vehicles) by analysing the time of the object movement opposite to the registration block and level of the reflected signal from the object. The paper presents theoretical description and experimental research of main principles of the system operation. Experimental research of the system model with selected optical-electronic components have confirmed the possibility of metal objects detection at the required distance (0.5 – 2 m) with different values of background illuminance.
The model of the optoelectronic positioning system of industrial equipment
One way of reduce costs for the assembly of high-precision large-sized products, such as planes or ships of different purpose is minimize of the time spent for control of geometrical parameters docking of large parts. Present systems do not have the high performance and do not have the ability to control multiple objects at the same time. The proposed system consists of at least four scanning devices and at least one position sensor. The paper describes a mathematical model of the system, as well as the stand for the study of the system. It is shown that the use of a many scanning devices enables high accuracy in determining the coordinates of the sensors and it allows to monitor multiple sensor networks at the same time.
Modelling of interference pattern produced by Michelson interferometer
Using of Michelson interferometer is shown in the field of measurement of periodical displacements of the con-trolled object. The foundations of optical interferometry are presented. The features of Michelson interferometer are described. The mathematical model of interference pattern produced by Michelson interferometer is created. It takes in consideration such parameters as the angles at which the mirrors are located and the lengths of two optical paths.
Design and research of the LED edge-lighting systems for displays
Currently, there is a tendency to minimize the lighting system of the displays of portable electronic devices. Various approaches are taken, including placing the lighting source on the edge of a display, which helps to decrease the size of the device significantly. However, edge lighting has some disadvantages, the most important of which being nonuniformity of illumination. Several methods can be applied to provide uniform illumination of displays with edge lighting. In the most modern displays, Brightness Enhancement Films (BEFs) are used together with the wedge lightguides.

In the project, we consider systems for the edge lighting of relatively small displays approximately 20 x 30 mm. Only one LED with nearly lambertian spatial distribution was used in the system. The optical system consisted of a wedge lightguide and a reflective surface, the surface can be either smooth or structured (with array of certain structure).

Various combinations of the wedge lightguides with the structured reflective surfaces were considered in the study, the designed variants were also compared to the systems with BEFs.

The designed systems provide acceptable illuminance uniformity for the central display zone, with small dark zones on the display margins. As a result of its simple construction and the ease with which it can be manufactured, the developed system, which has only one LED source, has potential applications in situations where the requirements for illuminance uniformity are not very high, for instance, in indicator devices.
Application of input amplitude masks in image encryption with spatially incoherent illumination for increase of decrypted images signal-to-noise ratio
Pavel A. Cheremkhin, Nikolay N. Evtikhiev, Vitaly V. Krasnov, et al.
The majority of existing methods of optical encryption use not only light intensity distribution, easily registered with photosensors, but also its phase distribution. This provides best encryption strength for fixed quantities of elements and phase levels in a mask. Downsides are holographic registration scheme used in order to register not only light intensity distribution but also its phase distribution and speckle noise occurring due to coherent illumination. That factors lead to very poor decryption quality when it comes from computer simulations to optical implementations.

Method of optical encryption with spatially incoherent illumination does not have drawbacks inherent to coherent systems, however, as only light intensity distribution is considered, mean value of image to be encrypted is always above zero which leads to intensive zero spatial frequency peak in image spectrum. Therefore, in case of spatially incoherent illumination, image spectrum, as well as encryption key spectrum, cannot be white. If encryption is based on convolution operation, no matter coherent light used or not, Fourier spectrum amplitude distribution of encryption key should overlap Fourier spectrum amplitude distribution of image to be encrypted otherwise loss of information is unavoidable.

Another factor affecting decrypted image quality is original image spectrum. Usually, most part of image energy is concentrated in area of low frequencies. Consequently, only this area in encrypted image contains information about original image, while other areas contain only noise. We propose to use additional encoding of input scene to increase size of the area containing useful information. This provides increase of signal-to-noise ratio in encrypted image and consequentially increases quality of decrypted images.

Results of computer simulations of test images optical encryption with spatially incoherent illumination and additional input amplitude masks are presented.
Principles of optical system construction for forming a cylindrical light tube
Kseniia Ezhova, Victor Zverev
In this paper the basic principles of the optical system construction for forming a cylindrical light tube of assigned diameter are formulated. It is based on the principle of agreement aperture and field angle of the optical system and the possibility of converting the transverse dimensions of the cylindrical light tubes by using the afocal optical system. In general, the task of converting a formed cylindrical light tube with the desired dimensions in the reverse path of the rays can be solved with a help of the single afocal system consisting of two positive components. In paper some variants of the optical system scheme for preliminary (initial) conversion of light tubes with an indication of their main advantages and disadvantages are presented. Aberration analysis of optical systems was carried out.
Simulation of multicomponent light source for optical-electronic system of color analysis objects
Development of lighting technology has led to possibility of using LEDs in the specialized devices for outdoor, industrial (decorative and accent) and domestic lighting. In addition, LEDs and devices based on them are widely used for solving particular problems. For example, the LED devices are widely used for lighting of vegetables and fruit (for their sorting or growing), textile products (for the control of its quality), minerals (for their sorting), etc. Causes of active introduction LED technology in different systems, including optical-electronic devices and systems, are a large choice of emission color and LED structure, that defines the spatial, power, thermal and other parameters. Furthermore, multi-element and color devices of lighting with adjustable illumination properties can be designed and implemented by using LEDs. However, devices based on LEDs require more attention if you want to provide a certain nature of the energy or color distribution at all the work area (area of analysis or observation) or surface of the object. This paper is proposed a method of theoretical modeling of the lighting devices. The authors present the models of RGB multicomponent light source applied to optical-electronic system for the color analysis of mineral objects. The possibility of formation the uniform and homogeneous on energy and color illumination of the work area for this system is presented. Also authors showed how parameters and characteristics of optical radiation receiver (by optical-electronic system) affect on the energy, spatial, spectral and colorimetric properties of a multicomponent light source.
Optical system design with variable working distance for monitoring of environmental contamination in infrared region
The project is dedicated to a research and development of a compact optical system for an identification of dangerous substances in a surrounding environment using a spectrum of scattered laser radiation. There is a whole class of tasks for diagnostics of environments and substances which are solved by mobile systems on distances of 0.5 – 10 m from the object.

The key feature of an optical system in this case is having the highest functionality, to meet this demands it should be able to work on variable distances and provide the minimal light spot. The purpose of the work is a research of the best possible initial system parameters and its components, designing of an optical system with minimum possible number of elements providing acceptable quality of the image in the required dimensions. An image quality criterion for such systems is the size of the light spot, which defines an operation speed of the system.

Using the beam diameter and allowable system dimensions as initial parameters of the two components system, relations were found which helps to define optimal component parameters for future design. To provide the possibility of working on various distances the thickness between the components can be varied.

An example of a two component system consisted of three lenses with spherical surfaces is presented. The system works with a laser with the wavelength of 0.785 μm and provides the light spot less than 2.3 mm for all working distances within the range of 2 – 5 m.
Demonstration of digital hologram recording and 3D-scenes reconstruction in real-time
Pavel A. Cheremkhin, Nikolay N. Evtikhiev, Vitaly V. Krasnov, et al.
Digital holography is technique that allows to reconstruct information about 2D-objects and 3D-scenes. This is achieved by registration of interference pattern formed by two beams: object and reference ones. Pattern registered by the digital camera is processed. This allows to obtain amplitude and phase of the object beam. Reconstruction of shape of the 2D objects and 3D-scenes can be obtained numerically (using computer) and optically (using spatial light modulators - SLMs). In this work camera Megaplus II ES11000 was used for digital holograms recording. The camera has 4008 × 2672 pixels with sizes of 9 μm × 9 μm. For hologram recording, 50 mW frequency-doubled Nd:YAG laser with wavelength 532 nm was used. Liquid crystal on silicon SLM HoloEye PLUTO VIS was used for optical reconstruction of digital holograms. SLM has 1920 × 1080 pixels with sizes of 8 μm × 8 μm. At objects reconstruction 10 mW He-Ne laser with wavelength 632.8 nm was used. Setups for digital holograms recording and their optical reconstruction with the SLM were combined as follows. MegaPlus Central Control Software allows to display registered frames by the camera with a little delay on the computer monitor. The SLM can work as additional monitor. In result displayed frames can be shown on the SLM display in near real-time. Thus recording and reconstruction of the 3D-scenes was obtained in real-time. Preliminary, resolution of displayed frames was chosen equaled to the SLM one. Quantity of the pixels was limited by the SLM resolution. Frame rate was limited by the camera one. This holographic video setup was applied without additional program implementations that would increase time delays between hologram recording and object reconstruction. The setup was demonstrated for reconstruction of 3D-scenes.
Development and analysis of new type microresonator with electro-optic feedback
Giedrius Janusas, Arvydas Palevicius, Elingas Cekas, et al.
Micro-resonators are fundamental components integrated in a hosts of MEMS applications: safety and stability systems, biometric sensors, switches, mechanical filters, micro-mirror devices, material characterization, gyroscopes, etc. A constituent part of the micro-resonator is a diffractive optical element (DOE). Different methods and materials are used to produce diffraction gratings for DOEs. Two-dimensional or three-dimensional periodic structures of micrometer-scale period are widely used in microsystems or their components. They can be used as elements for micro-scale synthesis, processing, and analysis of chemical and biological samples. On the other hand micro-resonator was designed using composite piezoelectric material. In case when microscopes, vibrometers or other direct measurement methods are destructive and hardly can be employed for in-situ analysis, indirect measurement of electrical signal generated by composite piezoelectric layer allows to measure natural frequency changes. Also piezoelectric layer allows to create a novel micro-resonator with controllable parameters, which could assure much higher functionality of micro-electromechanical systems. The novel micro-resonator for pollution detection is proposed. Mathematical model of the micro-resonator and its dynamical, electrical and optical characteristics are presented.
Investigations of spread function of the optical spectral device based on acousto-optic tunable filter
Vasily Kazakov, Georgy Korol, Oleg Moskaletz
The analysis of the spectra of the dynamic signals in optical range by techniques of acousto-optics at light diffraction on a traveling acoustic wave excited by a periodic sequence of radio pulses with a rectangular envelope and linear variation of the instantaneous frequency is considered. The expression of the spread function of the spectral device based on acousto-optical tunable filter that allows to investigate in detail the advantages of this optical spectrometer is obtained. Mathematical modeling of the spread functions for different values of speed of change of the instantaneous control frequency is performed. The results of experimental research are provided.
Design optimization of large-size format edge-lit light guide units
J. Hastanin, C. Lenaerts, K. Fleury-Frenette
In this paper, we present an original method of dot pattern generation dedicated to large-size format light guide plate (LGP) design optimization, such as photo-bioreactors, the number of dots greatly exceeds the maximum allowable number of optical objects supported by most common ray-tracing software. In the proposed method, in order to simplify the computational problem, the original optical system is replaced by an equivalent one. Accordingly, an original dot pattern is splitted into multiple small sections, inside which the dot size variation is less than the ink dots printing typical resolution. Then, these sections are replaced by equivalent cells with continuous diffusing film. After that, we adjust the TIS (Total Integrated Scatter) two-dimensional distribution over the grid of equivalent cells, using an iterative optimization procedure. Finally, the obtained optimal TIS distribution is converted into the dot size distribution by applying an appropriate conversion rule. An original semi-empirical equation dedicated to rectangular large-size LGPs is proposed for the initial guess of TIS distribution. It allows significantly reduce the total time needed to dot pattern optimization.
The impact of the semiconductor emitting diode brightness distribution on the energy sensitivity of the opto-electronic system with the optical equisignal zone
Ivan S. Nekrylov, Alexander N. Timofeev, Maksim A. Kleshchenok
The research of the influence of the LED radiation brightness distribution on the energy sensitivity of optical-electronic systems with optical equal zone is provided. Mathematical modeling of the radiation field on a matrix receiver, considering lens spherical aberration, is provided. The possibility of forming a uniform illumination on the photo-detector matrix, changing the shape of the distribution of the brightness of the LED at a predetermined invariable spherical aberration of the lens is provided.
Configurations of the reflector for optical-electronic autocollimator
Igor A. Konyakhin, Anastasia A. Moiseeva, Evgenii A. Moiseev
The problem of increasing working distance opto-electronic autocollimator in determining the angular position of the object was considered. It is proposed to use a reflector in the form of a quadrangular pyramid. We determined the measurement algorithm using the proposed reflector. Several types of retroreflectors with different reflective qualities were considered. The comparative analysis of these mirror systems and basic quadrangular pyramidal reflector are presented. The autocollimation system with pyramidal reflector is simulated and analyzed. Radiation passing through the autocollimation system with a pyramidal reflector is simulated.
The optics mechanical module for inter-satellite link
E. A. Tsyganok, B. N. Dobriakov
Inter-satellite link (ISL) is a system of several satellites, which encircle the earth and spaced at a fixed distance from each other - of about 3000 kilometers. The optical-mechanical module (MOM) for the ISL is designed to transmit data over long distances in a small range of angles.
Effect of interferences on indoor visible light car-to-car communication systems
Jong-Young Kim, Bong-Seok Park, Hyun-Sik Choi, et al.
We report the effect of interferences on visible light car-to-car communication system. The interferences from floor reflections and fluorescent lamps are taken into account for indoor car-to-car visible light communication (VLC) systems. The system is composed of a white LED lamp as a VLC transmitter and a photo-receiver with an appropriate optical filter as a VLC receiver. The signal power distribution patterns are measured and analyzed at a transmission distance, considering the positions of the transmitter and receiver. Generally, the light from fluorescent lamps in indoor environment affects the DC level of the received signal power, which is more significant at higher receiver positions. The measurements show that the indoor VLC communication performance can be varied depending on floor reflections. Also, the fluorescent ceiling illuminations affect the DC level change of the received VLC signal waveforms.
Technology optimization techniques for multicomponent optical band-pass filter manufacturing
Yuri P. Baranov, Georgiy M. Gryaznov, Andrey Y. Rodionov, et al.
Narrowband optical devices (like IR-sensing devices, celestial navigation systems, solar-blind UV-systems and many others) are one of the most fast-growing areas in optical manufacturing. However, signal strength in this type of applications is quite low and performance of devices depends on attenuation level of wavelengths out of operating range. Modern detectors (photodiodes, matrix detectors, photomultiplier tubes and others) usually do not have required selectivity or have higher sensitivity to background spectrum at worst. Manufacturing of a single component band-pass filter with high attenuation level of wavelength is resource-intensive task. Sometimes it's not possible to find solution for this problem using existing technologies. Different types of filters have technology variations of transmittance profile shape due to various production factors. At the same time there are multiple tasks with strict requirements for background spectrum attenuation in narrowband optical devices. For example, in solar-blind UV-system wavelengths above 290-300 nm must be attenuated by 180dB. In this paper techniques of multi-component optical band-pass filters assembly from multiple single elements with technology variations of transmittance profile shape for optimal signal-tonoise ratio (SNR) were proposed. Relationships between signal-to-noise ratio and different characteristics of transmittance profile shape were shown. Obtained practical results were in rather good agreement with our calculations.
Research of limits of applicability of an open-source equipment for development the optical equipment kit
This work devoted to a comparative study of different designs of optical equipment models to creating it in a best way, as well as a comparison of conditions and materials, of which these moutains are made of. For fasteners for optical elements required considerable precision. Speaking of affordable 3D printers, precision fasteners depends on many parameters.The relevance of the work is to study the characteristics of three-dimensional printing accuracy and limits of its application.
Comparing and analysis of design lightweight large mirrors for space basing
In this paper, we consider ways to facilitate such as (radial-circular, triangular, hexagonal); holes; contour cross section of various shapes (single arch and double arch); sandwich, honeycomb structures. we examine the comparison of traditional and not traditional materials for large optics.
Study of orthogonal polarization approximation for ordinary and extraordinary rays in ray tracing for uniaxial crystals
We study the assumption of orthogonal polarization for ordinary and extraordinary rays inside uniaxial crystals, using a closed-form expression for the angle between the polarizations. We highlight that orthogonality holds only when the crystal axis is rather coplanar to the ordinary and extraordinary wave vectors or orthogonal to the extraordinary wave vector, which are the same conditions for the extraordinary ray to stay in the plane of incidence. We show that in general the deviation from orthogonality is rather small, for it depends on the difference of the optical indices, and that negative and positive crystals have different behaviors. Using the paraxial approximation we derive expressions for the polarizations of rays and point out that even under the paraxial regime orthogonality does not hold. Specific examples for calcite and quartz are given.
Polychromatic optical radiation source for air tract monitoring system
Ivan S. Nekrylov, Alexander N. Timofeev, Maksim A. Kleshchenok
The modeling of a polychromatic optical radiation source for the air tract monitoring system is provided. The implementation is based on an idea of a photometric sphere.
Modern approaches for a design and development of optoelectronic measuring systems
Ivan S. Nekrylov, Valery V. Korotaev, Victor M. Denisov, et al.
In the world is the widespread adoption of measuring equipment of new generation, which is characterized by small size, high automation level, a multi-channel, digital filtering, satellite synchronization, wireless communication, digital record in long-term memory with great resource, powered by long-lived sources, etc. However, modern equipment base of the Russian institutions and the level of development of technical facilities and measuring technologies lag far behind developed countries. For this reason, the vacated niches are actively developed by foreign companies. For example, more than 70% instrumentation performing works on the territory of Russia, equipped with imported equipment (products of Sweden and Germany companies); the amount of work performed with German equipment is more than 70% of the total volume of these works; more than 80% of industrial measurements are performed using HEXAGON equipment (Sweden). These trends show that the Russian sector of measuring technology gradually become import-dependent, which poses a threat to the economic security of the country and consistent with national priorities. The results of the research will allow to develop the theory of formation of control systems of the displacement with high accuracy and unattainable for the existing analogue ergonomic and weight characteristics combined with a comparable or lower cost. These advantages will allow you to be successful competition, and eventually to supplant the existing system, which had no fundamental changes in the last 20 years and, therefore, retained all the drawbacks: large size and weight, high power consumption, the dependence on magnetic fields.
The transformation of the spatial distribution of the radiation the p-n junction in the LED
Design of optical-electronic devices and systems involves the selection of such technical patterns that under given initial requirements and conditions are optimal according to certain criteria.1-5 The original characteristic of the OES for any purpose, defining its most important feature ability is a threshold detection. Based on this property, will be achieved the required functional quality of the device or system. Therefore, the original criteria and optimization methods have to subordinate to the idea of a better detectability. Generally reduces to the problem of optimal selection of the expected (predetermined) signals in the predetermined observation conditions. Thus the main purpose of optimization of the system when calculating its detectability is the choice of circuits and components that provide the most effective selection of a target.
Analysis of holographic data storage using a PA-LCoS device
Holographic data storage systems (HDSS) have been a promising and very appealing technology since the first laser developments in the sixties. Impact of ongoing advances in the various components needs to be explored in its specific application to HDSS. In this sense, continuous progress is being produced in spatial light modulator (SLM) technology where parallel-addressed liquid crystal on silicon (PA-LCoS) microdisplays have replaced previous liquid-crystal displays (LCD) in most of optics and photonics applications. PA-LCoS microdisplays are well adapted to display phaseonly elements without coupled amplitude. In this paper, we analyse how PA-LCoS devices can also be used to display the widely applied binary intensity modulated (BIM) data pages. We also investigate hybrid-ternary modulated (HTM) data pages, which are very much demanding on the phase and amplitude modulation properties of an SLM. HTM data pages combine the ease of detection of BIM data pages, together with a large reduction of the DC term of the Fourier Transform of the data page. This reduction is necessary to avoid saturation of the recording material dynamic range. Simulated results show the magnitude of the expected DC term in the Fourier plane. We have verified the good performance of PA-LCoS to display BIM data pages. We have also obtained that pure HTM data pages cannot be produced with PA-LCoS devices, however, a rather close performance is obtained when implementing the pseudo-HTM data pages. In this work a more complete study of pseudo-HTM modulation is offered.
Standard source for certification of optical-electronic devices
Natalia I. Fastova, Anton A. Maraev, Gennady G. Ishanin
To reduce the error at the certification of optoelectronic devices, sources and detectors of the standard sources and its diaphragm must be thermally stabilized in order to create a uniform background. We developed an uncooled model blackbody TCID-100 with working temperature up to 100°C with a thermally stabilized transmitter and the diaphragm set. The developed model is a cylinder made of red copper with a conical cavity. Cone length was chosen empirically to provide uniform heating over the entire length of the blackbody cavity. With the developed model, we conducted cavity temperature measurement transmitter, which enabled to evaluate the advantages and drawbacks of the blackbody design. In this article we examined models of blackbodies, the most popular types of cavities and the calculation of the thermal emissivity for them. We have designed blackbody and measured the cavity temperature change over the time.
Alternative theory of diffraction grating spectral device and its application for calculation of convolution and correlation of optical pulse signals
A new, alternative theory of diffraction grating spectral device which is based on the mathematical analysis of the optical signal transformation from the input aperture of spectral device to result of photo detection is proposed.

Exhaustive characteristics of the diffraction grating spectral device - its complex and power spread functions as the kernels of the corresponding integral operator, describing the optical signal transformation by spectral device is obtained. On the basis of the proposed alternative theory the possibility of using the diffraction grating spectral device for calculation of convolution and correlation of optical pulse signals is showed.
Experimental evaluation of the optical quality of DMD SLM for its application as Fourier holograms displaying device
In this paper, the optical quality of micromirror DMD spatial light modulator (SLM) is evaluated and its applicability as an output device for holographic filters in dispersive correlators is analyzed. The possibility of using of DMD SLM extracted from consumer DLP-projector was experimentally evaluated by displaying of Fourier holograms. Software for displaying of holograms was developed. Experiments on holograms reconstruction was conducted with a different number of holograms pixels (and different placement on SLM). Reduction of number of pixels of output hologram (i.e. size of minimum resolvable element) led to improvement of reconstructed image quality.

The evaluation shows that not every DMD-chip has acceptable optical quality for its application as display device for Fourier holograms. It was determined that major factor of reconstructed image quality degradation is a curvature of surface of SLM or its safety glass. Ranging hologram size allowed to estimate approximate size of sufficiently flat area of SLM matrix. For tested SLM it was about 1.5 mm. Further hologram size increase led to significant reconstructed image quality degradation.

Developed and applied a technique allows to quickly estimate maximum size of holograms that can be displayed with specific SLM without significant degradation of reconstructed image. Additionally it allows to identify areas on the SLM with increased curvature of the surface.
Static and transient modeling of fast moving ball actuator as a display device
Jongmo Lee, Ho Won Yoon, MunPyo Hong, et al.
FMBA(Fast Moving Ball Actuator), developed as novel electronic-paper display, has already proven its operability and functionality. However, optimization issues related with low operating voltage, high refresh rate, fine pixel and higher display resolution, etc. are still remaining to be improved for a successful commercialization. In order to optimize such issues effectively, static and transient model were developed and verified by comparing the calculated results to the measured. The static model is based on the force balancing equation between the driving and the holding forces while the transient model is developed from Newton’s 2nd law by adding the inertia as well as the resistive damping forces caused by the surroundings. With the simplified static model, driving voltage of 30.71 V was obtained, which is reasonably matched to the measured voltage of 40 V. Based on the transient model, also, the transient response of the device can be estimated within reasonable margin. Considering the absence of reliable key parameters of surface roughness, static and dynamic frictional coefficient, and refractive indices, the developed static and transient models account well the experimental results and thus they are expected to contribute further improvements in FMBA.
Data transfer through beam steering using agile lensing
This paper presents a data transfer scheme using multi-focus tunable lenses. The design involves the use of a standard laser source and a variable focus agile lens to steer to the laser beam that passes through the lens. In our proposed system, the beam steer angle depends on an input electrical signal which drives the tunable lens. Therefore the beam steer angle is made to follow the variations in the input electrical drive signal. This is extremely interesting for data transfer applications as the data signal can be used as the input drive signal to the lens. The laser beam is steered according to the input data voltage levels and when the beam is incident on a photo-detector of a finite size, only a fraction of its total incident optical power is received by the photo-detector. This power contribution is proportional to the fraction of the total number of photons per unit area which are incident on the active area of the detector. The remaining photons which are not incident on the photo-detector do not contribute to the received power at the photo-detector. We present the theory of beam steering through a tunable lens and present a theoretical framework which governs data transfer through the proposed method. We also present the transfer function of the proposed system which helps us to calculate its essential theoretical performance parameters such as modulation depth and bit error rates. We also present experimental results to demonstrate efficient data transfer through the proposed method. As tunable lenses are primarily deployed in motion-free multi-focus cameras hence most of the modern portable devices such as cellphones and tablets use these lenses to operate the in-built variable focus cameras that are part of these devices. Because tunable lenses are commonly present in several different portable devices, the proposed method of data transfer between two devices is highly promising as it expands the use of the already deployed tunable lenses with minimal changes to the fundamental architecture or operation of any portable device.
Design and analysis of an optical FIR filter
Anuj Kumar Sharma, Sandeep Sharma, Santosh Kumar
In this paper, an optical finite impulse response (FIR) filter is proposed. An optical FIR filter can produce arbitrary spectrum output based on transfer function. The corresponding relationship between an optical filter and FIR filter is analyzed and analysis is presented in detail.
Sensitivity distribution of a vibration sensor based on Mach-Zehnder interferometer designed inside the window system
Interferometric sensors are very accurate and sensitive sensors that due to the extreme sensitivity allow sensing vibration and acoustic signals. This paper describes a new method of implementation of Mach-Zehnder interferometer for sensing of vibrations caused by touching on the window panes. Window panes are part of plastic windows, in which the reference arm of the interferometer is mounted and isolated inside the frame, a measuring arm of the interferometer is fixed to the window pane and it is mounted under the cover of the window frame. It prevents visibility of the optical fiber and this arrangement is the basis for the safety system. For the construction of the vibration sensor standard elements of communication networks are used - optical fiber according to G.652D and 1x2 splitters with dividing ratio 1:1. Interferometer operated at a wavelength of 1550 nm. The paper analyses the sensitivity of the window in a 12x12 measuring points matrix, there is specified sensitivity distribution of the window pane.
Fiber optic system design for vehicle detection and analysis
Fiber optic interferometers belong to a group of highly sensitive and precise devices enabling to measure small changes in the deformation shapes, changes in pressure, temperature, vibration and so on. The basis of their activity is to evaluate the number of fringes over time, not changes in the intensity of the optical signal. The methodology described in the article is based on using the interferometer to monitor traffic density. The base of the solution is a Mach-Zehnder interferometer operating with single-mode G.652 optical fiber at the wavelength of 1550 nm excited by a DFB laser. The power distribution of the laser light into the individual arms of the interferometer is in the ratio 1:1. Realized measuring scheme was terminated by an optical receiver including InGaAs PIN photodiode. Registered signal from the photodetector was through 8 Hz high pass filter fed to the measuring card that captures the analog input voltage using an application written in LabView development environment. The interferometer was stored in a waterproof box and placed at the side of the road. Here panned individual transit of cars in his environs. Vertically across the road was placed in contact removable belt simulating a retarder, which was used when passing cars to create sufficient vibration response detecting interferometer. The results demonstrated that the individual vehicles passing around boxing showed characteristic amplitude spectra, which was unique for each object, and had sufficient value signal to noise ratio (SNR). The signal was processed by applications developed for the amplitude-frequency spectrum. Evaluated was the maximum amplitude of the signal and compared to the noise. The results were verified by repeated transit of the different types of cars.
Effect of the geometric deformations on the Brillouin scattering in the standard single-mode optical fiber
Distributed optical fiber sensors monitor the measured variables over the entire fiber length. Distributed strain and temperature system (DSTS) scans the frequency change of Brillouin scattering which depends on the measured temperature and mechanical stress of the fiber. This paper deals with the effect of fiber geometric deformations on the Brillouin scattering. The points of maximum and minimum deformations were searched using the Brillouin frequency change. The optical fiber was installed into base geometric shapes and deformed by mechanical stress. Standard single-mode fiber G.652.D was used. The aim of this study was to verify if the standard optical fiber originally designed for telecommunication transmissions are suitable for sensor applications with DSTS. It turned out that these fibers are applicable for the deformation measurement and geometrical arrangement has great influence on the measurement sensitivity too.
Mathematical model of optimized design of multi-point sensoric measurement with Bragg gratings using wavelength divison multiplex
Fiber Bragg gratings (FBGs) belongs to the single-point optical sensors used in many fields and applications where they often replace a standard sensors. They are easy to multiplex and the wavelength division multiplex is the most widely used method. FBGs in sensory branch are designed for a different Bragg wavelength which gives different measure and sensitivity coefficients. Existing algorithm is based on the determination of left and right boundaries of the measuring channel and the central Bragg wavelength. In this paper is presented the new mathematical model for calculation of Bragg wavelength, sensitivity coefficient and channel width of any FBG in the single step. The model takes into account the following input parameters: wavelength of the optical source, source bandwidth, the type of measured quantity, measuring ranges, width of the FBG reflected spectrum and the guard band between adjacent channels. The mathematical model is verified by using a simulation in software OptiSystem.