Efficient and successful optical design requires a multidisciplinary approach. The optical designer needs to have material and production expertise, knowledge of the application and potential market, in addition to considerable ability in their main task; the design of an optical system with optimum performance. Advanced optical systems require a clear understanding of the physical limits, material science, and technical possibilities. Only then will the result be a competitive product optimised for best value for money. In many cases, the success of a product in the international marketplace depends on its optical design.
: The design software is the main tool for the designer. This tool has to keep pace with the research and development activities in the field of optical elements, illumination, detectors, and other new technologies.

Contributions on the topics of design-to-cost, design-for-manufacture, including productions in series as example for space constellations or military programs, and design-for-industrial innovation are welcome at this conference. These topics are critical to ensuring that optical designs more effectively accommodate production constraints and new process developments in an increasingly competitive environment.

This conference is intended to address an international audience of optical system designers, software development engineers, and R&D experts from industry, institutions, and academia.

Original papers are solicited on, but not limited to, the following areas of research, design, and engineering of optical systems: ;
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Conference 11871

Optical Design and Engineering VIII

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  • Plenary Session I: Monday
  • Plenary Session II: Tuesday
  • Networking Session
  • Welcome and Introduction
  • Optomechanical Design I
  • Freeform Optics
  • Modelling and Simulation I
  • Introductory Remarks
  • Micro- and Diffractive Optics
  • Intergrated and Guided Optics
  • Space Optics
  • Optics for Visual Instruments
  • Optomechanical Design II
  • Modelling and Simulation II
  • Detectors and Microscopy
  • Poster Session
Plenary Session I: Monday
Livestream: 13 September 2021 • 09:00 - 11:00 CEST
11871-500
Author(s): Vladan Blahnik, Carl Zeiss AG (Germany)
On demand | Presented Live 13 September 2021
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The iconic photos of NASA's first space missions and Moon landings from the 1960s onwards were captured with ZEISS camera lenses mounted on Hasselblad cameras. They adorned the covers of many newspapers and magazines and appeared in color for the first time ever, as special issues. Meanwhile, NASA's scientists were evaluating the scientific images: the photogrammetric images taken while in orbit were combined to form a detailed lunar map, the panorama pans on the lunar surface were turned into a topographic map of the landing area, and the pictures with broadband achromatized UV lenses gave insights into the overall soil conditions on the Moon and the Earth. The talk will provide an overview of all the camera lenses developed by ZEISS for NASA. It will look at their technical specifications, describe the development work done for these lenses, and delve into the history of the partnership between NASA, Hasselblad, and ZEISS. Just like space travel, the launch of mainframe computers at that time also spurred on optical design. Other ZEISS products for photography, cinematography, aerial photogrammetry, and optical lithography also benefited from these developments.
11871-501
Freeform optics design (Plenary Presentation)
Author(s): Pablo Benitez, Univ. Politécnica de Madrid (Spain)
On demand | Presented Live 13 September 2021
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The higher flexibility of freeforms has opened the possibility to find better solutions than classical surfaces many optical problems, especially those whose specifications (either optical or geometrical) are far from rotational symmetry. For instance, short through distance multimedia projectors cannot be placed in front of the center of the projected image without blocking the spectators’ view, and this requires the projection to be done from one side. Offset rotational symmetric solutions are suboptimal, and a freeform projector can improve the image quality on the target area with the same number of surfaces or can match the quality with fewer optical surfaces 1. Similarly, many head-worn displays are located close to the eyes of the user to make the headset sleeker. In this case, some parts of the physical display are used at very high emitting angles and rotational symmetric cannot provide optimal solutions for this configuration. In nonimaging applications, low-beam headlamps of cars also need to produce an asymmetric pattern on the road to avoid blinding the incoming drivers. Freeforms permit to solve this design problem efficiently, and match aesthetic constraints. The continuous progress in the technology to produce and test freeforms, as occurred in the past with rotational aspherics, is pushing optical designers to consider more and more the use of freeforms in their designs. However, the also higher complexity of these surfaces introduces multiple challenges in their design since traditional design methods have been focused in rotational optics. These challenges go from finding the best mathematical description of the optical surfaces to the design algorithms themselves. We’ll review the main design techniques proposed to design freeforms and illustrating its use in specific examples for several applications.
Plenary Session II: Tuesday
Livestream: 14 September 2021 • 16:00 - 18:00 CEST
11871-600
Lens design through the ages (Plenary Presentation)
Author(s): John R. Rogers, Synopsys, Inc. (United States)
On demand | Presented Live 14 September 2021
11876-601
Author(s): Bernard C. Kress, Microsoft Corp. (United States)
On demand | Presented Live 14 September 2021
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For the past decade, optics and display hardware developments for mixed reality and smart glasses were merely a shot in the dark, providing enough display immersion and visual comfort for developers to build up apps, especially for the enterprise field. Today, as universal use cases for consumer emerge such as co-presence, digital twin and remote conferencing, new optical functionalities are required to enable such experiences. It is not only a race to smaller form factor and light weight devices for large field of view (FOV) and lower power, but the requirements are also on additional display and sensing features specifically tuned to implement such new universal use cases. Broad acceptance of wearable displays especially in the consumer field is contingent on enabling these new display and sensing requirements in small form factors and low power. This talk will focus on waveguide combiner technologies and how these architectures have evolved over the past years to address such new requirements
Networking Session
Livestream: 15 September 2021 • 11:00 - 12:30 CEST
11871-700
15 September 2021 • 11:00 - 12:30 CEST
Welcome and Introduction
Opening Remarks by conference chairs.
Optomechanical Design I
Session Chairs: Laurent Mazuray, Airbus Defence and Space (France), James Babington, Thales Optronics Ltd. (United Kingdom)
11871-1
Author(s): Marta C. de la Fuente, ASE Optics Europe (Spain); Luis Pascual de la Torre, Thales Alenia Space (Spain); Paloma Matia-Hernando, Andrés Cifuentes, Zaira M. Berdiñas, ASE Optics Europe (Spain)
On demand
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The Cubesat-compatible Morera optical instrument is a very compact, low f/n LWIR camera designed to provide high resolution images at farm level to estimate evapotranspiration data and provide personalized irrigation recommendations directly to final users using a mobile device. A SW-defined system will use Big Data to combine all relevant information (AEMET, Copernicus, S-SEBI algorithms) to optimize water resources. Catadioptric systems are extensively used in very compact systems. However, the more compact the system the more difficult it is to implement baffles to shield any light not coming from the field of view. The search for a compact configuration that meets straylight performance is described in this paper. The selective spectral bandpass filter requires angles of incidence below 0.5º, adding telecentricity to the key requirements. Finally, photogrammetry imposes the need of low distortion, which can be controlled by freeforms while achieving the goal on angle of incidence.
11871-3
Author(s): Michelle C. Rocha, Alexander V. Goncharov, National Univ. of Ireland, Galway (Ireland)
On demand
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A quasi-aplanatic two-lens design is proposed to correct astigmatism in Ritchey-Chrétien (RC) telescopes at different spectral bands. This pair of lenses is designed analytically so that it can be used in existing RC telescopes without any modification of the mirror's shapes while introducing only a small amount of coma. The field of view (FoV) is consequently increased due to the astigmatism being corrected by the two lenses and due to the final image being flattened. Furthermore, astigmatism can be corrected individually for each spectral band by merely changing the distance between the two lenses.
11871-4
Author(s): Javier Moreno Raso, Eloi Vázquez, Diego Saez, José Domingo Meléndez, José Manuel Sánchez Cercós, Lucas Salvador, Jesús Aivar Mateo, LIDAX (Spain)
On demand
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LIDAX, a Spanish company located in Madrid specialized in the Development of optical and optoelectronic equipment for advanced scientific instrumentation for both space applications and terrestrial astronomical facilities, has been selected by the Institute of Astrophysics of the Canary Islands to develop, manufacture, test and deliver a Laser Launch Telescope for the creation of artificial stars, forming part of the Laser Guide Star (LGS) Facility for the Gran Telescopio Canarias (GTC) Adaptive Optics System (GTCAO). This Laser Guide Star system, together with the GTC Adaptive Optics System will allow to make observations with high spatial resolution at the diffraction limit of the GTC. This is equivalent to make these observations as if the GTC telescope were in Space, as the Hubble Telescope or the future JWST, without any effect from Earth’s atmosphere. The Laser Launch Telescope has unique features in terms of propagation stability, launching a laser beam at the wavelength of sodium (589 nm) into the sky, with a very high optical quality. This laser beam will stimulate the sodium atoms that are present in the upper atmosphere and will create an artificial star, at an height of 90 km, with the necessary characteristics and optical quality to allow the functioning of the GTC’s Adaptive Optics System, known as GTCAO, whose function is essential to eliminate the effect of atmospheric turbulence in the images taken by the telescope, and to obtain much sharper images. These adaptive optics systems are essential in large astronomical telescopes like the GTC. As many of the stellar object of interest have low luminosity or are not bright enough, high-brightness artificial stars are created by lasers next to the non-bright object to be observed, allowing the adaptive optics systems work correctly and correct the images in real time obtained from the object of interest. This unique system, installed on the GTC elevation ring, will make possible to exponentially increase the capacity of the Gran Telescopio de Canarias (GTC), a world-renowned Spanish astronomical facility located at Roque de los Muchachos in La Palma (Canary Islands). This pioneering project in Spain will provide to the GTC with the first laser launch telescope of these characteristics becoming an excellent reference for any other Astronomy Observatories that need this type of Telescopes for Laser Guide Systems as part of its Adaptive Optics Systems, or for other applications in different markets such as Defense, Space, or Big Science, where a laser beam needs to be propagated up to several km with a high optical quality. In addition, LIDAX will count with the technical experience of the IAC team with a great knowledge on these type of systems, the participation from a Dutch technology company that will supply the telescope lenses, and finally the technical support of the Space Instrumentation Laboratory of the National Institute of Aerospace Technology (INTA-LINES). LIDAX acting as the main Contractor of the Project will led the activities for its development, manufacture, assembly and optical tests, together with the rest of the partners.
Freeform Optics
Session Chair: Ulrike Fuchs, asphericon GmbH (Germany)
11871-5
Author(s): Simon Thibault, Univ. Laval (Canada), Immervision (Canada)
On demand
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Freeform surface is one of the main advanced in lens design over the last two decades. These advances motivated by the new fabrication process and new equipment are now closed to maturity. Recently we start finding on the market more and more camera phone that claims to use freeform lenses. None of these suppliers explained how and why freeform lenses are required in details. In this presentation, we will dive into this to found answers. At the time of writing this abstract, we can identify three camera phones that use freeform lenses. The first one is the Huawei Mate 40 Pro+, which seems to be the first worldwide freeform lens used in a cell phone. Huawei uses the freeform to compensate distortion (they call it ‘anti-distortion’). The lens is an f/1.8 for a 20MP sensor. A second one is the OnePlus 9 Pro, which uses an f/2.2, 7 plastics for a 50MP as an ultra-wide camera. Finally, Oppo Find X3 Pro is also using freeform lens (f/2.2) on an IMX766 50MP (Sony sensor). From all the publicity from those camera-phones, we can found that the freeform used to compensate distortion in the corner of the image. Somehow, we can ask if it is a freeform lens or not, is it only marketing? We will add to this discussion some laboratory results from the Huawei freeform lens as well as image taking with the various cell phone.
11871-6
Author(s): Ziyao Tang, Friedrich-Schiller-Univ. Jena (Germany); Herbert Gross, Friedrich Schiller University Jena (Germany)
On demand
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Compared to the rotationally symmetric systems, the surface-decomposed aberrations of the symmetry-free system is harder for analysis, due to the invalidity of the conventional paraxial reference. To solve this problem, a novel higher-order aberration calculation method for symmetry-free systems is proposed based on the mixed ray-tracing method, which is proved as a good approximation of the full-order transverse aberration for generalized systems. Furthermore, the method is also applicable for intrinsic/induced aberration calculation, as well as the surface additive Zernike coefficient fitting. With various potential implementations, the method is considered a convenient and powerful tool for aberration analysis of off-axis systems.
11871-7
Author(s): Lien Smeesters, Vrije Univ. Brussel (Belgium); Sebastian Donner, Mr Beam Lasers GmbH (Germany); Hugo Thienpont, Michael Vervaeke, Vrije Univ. Brussel (Belgium)
On demand
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Laser cutters are currently finding their way from industrial environments to home-use applications, driving the development towards low-cost and compact systems. We therefore target the design of a single beam-shaping lens for use in laser cutting applications, enabling the miniaturization of the laser scanning head while pursuing optimal cutting performance. Particularly, we target the design of a beam shaping lens for use with a high-power 450 nm laser diode (5.0 Watt, 14° x 46° beam divergence), enabling to transform the divergent elliptical laser diode beam into a circular focused spot, while maximizing the depth-of-focus. We cover the complete development chain, starting from the characterization and modelling of the laser diode, to the optical design, optimization and tolerancing of the focusing lens, and the manufacturing and demonstration of the laser cutting system. The optimized beam-shaping lens features a circular focused spot diameter <100 µm over a depth-of-focus of 4.8 mm. In contrast to the current laser diode circularization and focusing designs, comprising a combination of cylindrical and plano-convex lenses, we only use a single aspheric biconic lens, giving rise to a more compact design. A tolerance analysis was included on both the optical and mechanical parameters, enabling to evaluate the design for manufacturing. Following, the novel beam-shaping lens was manufactured using ultraprecision diamond turning, and afterwards characterized using a coordinate measurement machine. Finally, the performance is evaluated in a proof-of-concept demonstrator, validating the circular illumination beam and improved cutting performance. We successfully demonstrated the operation of our novel beam-shaping lens, featuring the beam circularization and focusing using a single lens, optimized for use in compact laser cutting devices. This novel lens design paves the way towards a further miniaturization of desktop laser cutters, while showing an excellent laser cutting performance, including an improved cutting resolution and depth-of-focus, enabling a wider range of materials and extended material thicknesses.
Modelling and Simulation I
Session Chair: James Babington, Thales Optronics Ltd. (United Kingdom)
11871-8
Author(s): Mariia K. Orekhova, Alexey V. Bakholdin, ITMO Univ. (Russian Federation)
On demand
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Many astronomical studies require obtaining detailed information about the spectrum of a celestial object, for which various types of spectrometers are effectively used. In the case of extended fields, it becomes necessary to optimally match the field image of an objective and the entrance slit of a spectrometer. For that, an optical scanning system is used. However, it becomes impossible to capture different events in real time this way. For the simultaneous capturing of a wide field, it is efficient to use an integral field unit (IFU). IFU is the optical system that allows slicing and transforming of a field into a set of long slits that are fed to a spectrometer. The design of the IFU optical system for the solar telescope-coronagraph (LST-3) is presented. LST-3 is the telescope with the main mirror of 3m, and it should operate in the wide spectral range, 0.4-1.6 μm. The telescope's objective field of rectangular shape, (1.1 x 2.2) mm, is transformed in two steps: slicing the image and reorganization of sub-images into a set of 8 long slits, (0.018 x 18.6) mm. The reorganization is performed using the system of two flat mirrors. The mirrors are rotated around two axes, which entails the accumulating error of a sub-image position in the image plane. For studying the offset error in an IFU, a simulation was performed. The expression of the error function makes it possible to consider it when using an IFU, while maintaining high spatial resolution and co-directionality of sub-image apertures in the slit plane. As a result of the work, it was confirmed that the use of two flat mirrors for geometric image transformation is possible when designing an IFU.
11871-10
Author(s): Michelle Grüne, Alicia Charlotte Rimbach, Stefan Schweizer, Fachhochschule Südwestfalen (Germany)
On demand
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Luminescent borate glass represents an interesting alternative as light-converter for LED applications. They provide a high transparency, a wide glass-forming range, a good chemical stability, and a good solubility for lanthanide ions. In this work, Dy3+-activated light guides made of borate glass are investigated for their optical properties. The optical activation with Dy3+ ions enables for an intense green-yellowish luminescence upon excitation in the UV / blue spectral range. To investigate the luminous intensity distribution as well as the angle-dependent emission spectra, the light guide is placed in front of LEDs emitting in the UV / blue spectral range. The experimental results are complemented by ray-tracing simulations. The effect of surface roughness, in particular of the front faces is studied in detail as it is an important factor for the light output. Also, the improvement of the light guiding properties by applying a reflecting coating to the side faces is investigated.
Introductory Remarks
Welcome Address: "TRL and MRL : a common scale from innovation to implementation"
Laurent Mazuray, Airbus Defence and Space (France)
Micro- and Diffractive Optics
Session Chair: Ulrike Fuchs, asphericon GmbH (Germany)
11871-12
Author(s): Guillaume Druart, Florence de la Barrière, Jean-Baptiste C. G. Volatier, ONERA (France); Elodie Tartas, LYNRED (France); Raphaël Proux, John Franks, Umicore IR Glass (France); Susanne Ehret, Fraunhofer-Institute (Germany)
On demand
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Infrared cameras could serve automotive applications by delivering breakthrough perception systems for both in-cabin passengers monitoring and car surrounding. However, low-cost and high-throughput manufacturing methods are essential to sustain the growth in thermal imaging markets for automotive applications, and for other close-to-consumer applications which have a fast growth potential. Fast low cost infrared lenses suitable for microbolometers are currently already sold by companies like Umicore, Lightpath, FLIR… They are either made of a single inverse meniscus Chalcogenide glass or of two Silicon optics. In this paper, we explore hybrid systems with a large field of view around 40° combining Chalcogenide and Silicon in order to take advantage of both materials. Both are compatible with wafer-level process. Silicon optics can be manufactured by photolithography process and are expected to be more cost-effective than Chalcogenide ones. However they are constrained in shape and sag height. On the other hand, Chalcogenide optics can be collectively molded and could have more free shapes. They are thus more suitable to reach high-demanding performance. So hybrid designs could be seen as a compromise between cost and performance. In this paper, we show that fast lenses with diameter constraints to few millimeters to make affordable wafer-level process lead to small size detectors. As a consequence, the pixel pitch reduction of microbolometers is a key point to maintain a good resolution. Finally, strategies to improve the production yield of hybrid lenses are explored.
11871-13
Author(s): James Babington, Thales Optronics Ltd. (United Kingdom); Andrew P. Wood, Freelance Optics Consultant (United Kingdom)
On demand
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Hybrid diffractive lenses are an enabling technology that allows the shaping and control of wavefronts by precisely controlled zone structures. In particular, they are extremely useful in the medium and long wave infrared spectral regions for performing colour correction, where the lens element count can be reduced (replacing two heavy and expensive infrared materials with a single element). Yet these surface structures are often modelled in a way that treats the surface purely as an attached phase function and not an actual physical structure. This makes some results dubious and provides a substantial difficulty in assessing and specifying tolerances. In the current presentation, we move to a more physical model based on the ideas of zone decomposition.
11871-38
Author(s): Eduard R. Muslimov, Tibor Agócs, Ivan Lloro, ASTRON (Netherlands); Adrian M. Glauser, ETH Zurich (Switzerland); Olivier Absil, Liège Univ. (Belgium); Dennis Dolkens, Niels Tromp, Daan Zaalberg, ASTRON (Netherlands)
On demand
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The Mid-infrared ELT Imager and Spectrograph (METIS) is one of the three first-generation instruments onthe Extremely Large Telescope (ELT). It will provide 20 instrument configurations for direct and high-contrastimaging, medium and high resolution spectroscopy in the wavelength range of 3−13 microns. The straylight willaffect the image contrast and objects recognition thus influencing the final instrument performance. For thisreason it should be taken into account and accurately modeled at the design stage. In the present study weconsider straylight from the following sources: surface roughness and defects of the optical surfaces, multiplereflections and diffraction, which will all influence the instrument performance. We estimate their influence usinga bottom-up modelling approach at the system level and derive the requirements for some critical parameters.Using empirical and analytical models and performing non-sequential raytracing we demonstrate that the targetstraylight level can be reached in the current design with reasonable specifications on the optical components.
11871-15
Author(s): Ruslan V. Shimansky, Dmitrij A. Belousov, Roman I. Kuts, Victor P. Korolkov, Institute of Automation and Electrometry of the SB RAS (Russian Federation)
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Controlling an accuracy of fabricating computer-generated holograms (CGH) is actual task. Such holograms are usually used for generating reference wavefront for interferometric testing of aspherical surfaces. The influence of external factors on the positioning systems of the writing system occurs during fabricating the holograms and leads to microstructure errors that affect the quality of the wavefront formed by such elements. Fabrication errors of CGH affect the accuracy and reliability of interferometric measurements. Controlling these errors allows determining the quality of the manufactured element and evaluating the accuracy of the wavefront which it forms. This paper presents the experimental results of using CGH error testing methods for laser writing systems that operate in a polar or cartesian coordinate system. These methods are based on writing of series of embedded small marks with gratings having 2-5 µm period and following measurement of light intensities in curtain diffraction orders. These marks consist of two parts, one of which is quickly formed before the fabrication of CGH and the second one during writing the pattern of the main CGH. The shift between the first and second segments of the mark makes it possible to determine the CGH writing errors caused by external influences on the positioning system for both circular and X-Y laser writing systems. To determine writing errors can be use simple optical diffractometer.
Intergrated and Guided Optics
Session Chair: James Babington, Thales Optronics Ltd. (United Kingdom)
11871-23
Author(s): Daniel Schäffer, Daniel Klenkert, Julian Stauch, Alois Kasberger, Technische Hochschule Deggendorf (Germany); Stephan Kufner, Deggendorf Institute of Technology (Germany); Maria Kufner, Technische Hochschule Deggendorf (Germany); Raimund Foerg, Deggendorf Institute of Technology (Germany)
On demand
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A new process for prototype manufacturing of integrated optical components was investigated. Sodium ions near the surface of a glass wafer are exchanged with silver ions, which creates a layer of increased refractive index. Subsequently, parts of the glass surface are ablated using a femtosecond laser. The resulting ridges determine the final optical waveguide structure. However, manufacturing-related roughness leads to high optical losses. To reduce these losses and to optimize the index profile, a second ion exchange with sodium ions is performed. These ions are introduced into the glass from all three ridge surfaces, causing the silver ions to migrate towards the ridge center. This results in a gradient index waveguide. We created a numerical model, to simulate the ion exchanges. Experiments were conducted, to determine the parameters for the ion exchange and the laser ablation. Based on the results, a process window was defined for each step, thus enabling the manufacturing of integrated optical components.
Space Optics
Session Chair: Laurent Mazuray, Airbus Defence and Space (France)
11871-18
Author(s): Grzegorz W. Fluder, Zdzisław Choromański, Jerzy Krezel, Solaris Optics S.A. (Poland); Michal Józwik, Warsaw Univ. of Technology (Poland)
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Space-based telescopes are very important tools in astronomy and Earth observations. They enable astronomical observation in spectral ranges outside of the atmospheric window, e.g. in ultraviolet below 300 nm. When designing a space telescope, it is desired to decrease the mass of the system. One of the ways to achieve it is to use diffractive optical elements. They have unique capabilities when it comes to aberration corrections. By combining refractive and diffractive elements in hybrid systems it is possible to obtain a well-corrected system with fewer elements compared to purely refractive systems. We present an optical design of a hybrid refractive-diffractive telescope working in the 200 nm – 300 nm spectral range with improved performance and decreased mass compared to refractive system. The telescope is designed to have a large field of view 10°x10°, enabling photometric observations of a large number of objects simultaneously, focal length of 150 mm and f-number equal to F/1.67. We compare the performance of two similar systems optimized using different merit functions. In one case the goal was to minimize the wavefront error and spot size, in the other a point spread function with larger full width at half maximum was obtained in order to avoid undersampling. We show the results of the tolerance analysis, which proves that the requirements for imaging quality may be fulfilled with moderate manufacturing and assembling tolerances. The influence of the antireflective coating on the efficiency of the diffractive lens is discussed. Based on the simulations performed using Fourier Modal Method we show that the AR coating deposited on the diffractive structure gives an increase of the efficiency at the expected level, provided that the profile height and the layers thicknesses is small enough compared to the zone widths and prove that this requirement is fulfilled in the described case.
11871-19
Author(s): Chanisa Kanjanasakul, Christophe Buisset, National Astronomical Research Institute of Thailand (Thailand); Thierry Lepine, Institut d'Optique Graduate School (France), Lab. Hubert Curien (France); Weerapot Wanajaroen, Boonrucksar Soonthornthum, Saran Poshyachinda, National Astronomical Research Institute of Thailand (Thailand)
On demand
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The Thai National Telescope (TNT) is the largest telescope in Southeast Asia with a primary mirror of 2.3-meter diameter located at altitude 2457 meters, Chiang Mai, Thailand. This telescope is equipped with two photometric cameras and a medium resolution spectrometer. The maximum instantaneous field of view (FOV) is circular of diameter equal to 15 arcminutes, provided by the camera called the “TNT Focal Reducer”. In this paper, we present the design and performance estimation of a prime focus camera for the TNT with the objective to reach a FOV equal to 1 degree. The TNT prime focus camera is specified to operate over the spectral domain 0.400-0.850 µm for spectral bands g’, r’ and i’ of the Sloan Digital Sky Survey (SDSS) photometric system. This camera is designed to reach a resolution better than 2 arcseconds, slightly above the seeing limit in median atmospheric conditions. The prime focus camera is planned to be installed at the secondary mirror (M2) and mounted on a hexapod manufactured by Physik Instrumente (PI) company. This hexapod will provide a positioning accuracy of ±2.5 μm of 3-axis translation. The orientation will be adjusted with an accuracy equal to ±1.03 arcseconds of rotation. The prime focus camera comprises five lenses made of S-FPL53, N-BAK2, SF1, BAF50 and SK3. This camera includes one aspherical concave surface of conic constant equal to -0.076 and the other surfaces are spherical. We have dedicated tolerance analysis to calculate the effects of manufacturing errors, alignment errors and stability on the operational performance. The results show that the operational angular resolutions over the full field of view should be better than 1.61 arcseconds. The results of the stray light analysis show that the ghost irradiance should be five orders of magnitude smaller than the image irradiance, assuming that the second lens of the camera and the detector window have an Anti-Reflective coating of reflectivity lower than 1%.
11871-46
Author(s): Paolo Chioetto, CNR/IFN Padova (Italy); Enzo Pascale, La Sapienza Università di Roma (Italy); Paola Zuppella, CNR/IFN Padova (Italy); Emanuele Pace, Università degli Studi di Firenze (Italy); Andrea Tozzi, INAF-Osservatorio Astrofisico di Arcetri (Italy); Giuseppe Malaguti, INAF-Osservatorio di Astrofisica e Scienza dello spazio di Bologna (Italy); Giuseppina Micela, INAF-Osservatorio Astronomico di Palermo (Italy)
On demand
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Ariel is ESA M4 mission to survey exoplanet atmospheres through transit spectroscopy in the 0.5-7.8 µm waveband. Launch is scheduled for 2029. Ariel payload consists of a 1-m class, all-aluminum telescope operating below 50 K. Telescope mirrors will employ a protected silver coating to improve reflectivity and to prevent degradation. An initial estimation of the overall throughput achievable by the telescope for the entire scientific duration of the mission is presented here. The starting point is the reflectivity of the coated mirrors as measured on samples, and throughput losses caused by surface roughness, particulate and molecular contamination, and cosmetic defects.
Optics for Visual Instruments
Session Chair: James Babington, Thales Optronics Ltd. (United Kingdom)
11871-20
Author(s): Lucie Sawides, 2EYES VISION (Spain); Alberto de Castro, Instituto de Óptica "Daza de Valdés" (Spain); Carmen M. Lago, 2EyesVision (Spain), Instituto de Óptica "Daza de Valdés" (Spain); Xoana Barcala, 2EYES VISION (Spain), Instituto de Óptica "Daza de Valdés" (Spain); Amal Zaytouny, Susana Marcos, Instituto de Óptica "Daza de Valdés" (Spain); Carlos Dorronsoro, 2EYES VISION (Spain)
On demand
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As a large variety of intraocular lens (IOL) designs is commercially available in a growing market, selecting the best IOL for each patient has become a crucial task for a positive surgical outcome. Information about the measured or estimated performance of commercial lenses, as the through-focus modulation transfer function (TF-MTF) at a given frequency and pupil diameter, is routinely published. SimVis Gekko, a see-through simultaneous vision simulator based on temporal multiplexing, allows patients to experience the real world through different multifocal corrections prior to surgery. Implementing the maximum number of commercially available IOL designs into the portfolio of SimVis Gekko simulations is needed to provide a complete experience for the patients. We developed a new method to visually simulate IOL designs using temporal multiplexing, based only on publicly available information (mainly scientific literature or regulatory information), using the TF-MTF at 15cpd as input data to estimate the temporal coefficients that provide the best approximation to the real lens design. We validated the method with synthetic phase maps of equal area segmented bifocal and trifocal multifocal corrections for three pupil diameters of 3mm, 3.75mm and 4.5mm and applied it to three commercially available IOLs (trifocal or extended-depth-of-focus lenses). Through-focus visual acuity (TF-VA) curves were measured in seven patients using the SimVis simulations in the SimVis Gekko and matched, on average, the through-focus VA measurements in patients with implanted IOLs, reported in the scientific literature (on average logMAR RMS error=0.05, corresponding to less than 3 letters of visual acuity charts).
11871-21
Author(s): Alice Fontbonne, Hervé Sauer, François Goudail, Lab. Charles Fabry (France)
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Today, almost all imaging systems include both an optical part and an image processing part in order to improve the final image quality. It therefore seems natural to optimize them simultaneously to obtain the best possible result. However, even if this “co-design” approach is more and more recognized at a conceptual level, it is still rarely used in practice for designing complex lenses with many adjustable parameters and constraints. This is due to the fact that the contribution of image processing is currently difficult to take into account in optical design software. Until now, the field of co-design has thus mainly focused on simpler imaging systems, consisting for example of single co-optimized optical elements such as phase masks. More recently, Robinson & Stork have been working on the possibility of integrating the image processing criterion known as mean square error (MSE) in the optical software Zemax OpticStudio. It is also possible to consider surrogate criteria instead of this MSE, built from more classical optical criteria (modulation transfer function, point spread function, etc.) [Burcklen et al. (2018)]. In this study, we investigate the possibility of implementing the MSE criterion in the CodeV optical design software in a way that is easily usable by an optical designer. We compare systems co-designed with this approach to systems jointly optimized with surrogate criteria or conventionally optimized. We focus on the performance differences between these different approaches and on the opportunities offered by CodeV for co-design.
11871-22
Author(s): Xoana Barcala, 2EYES VISION (Spain), Visual Optics and Biophotonics Lab. (Spain); Enrique Gambra, Lucie Sawides, 2EYES VISION (Spain); Ivan Martinez-Ibarburu, Victor Rodriguez-Lopez, Visual Optics and Biophotonics Lab. (Spain); Carlos Dorronsoro, 2EYES VISION (Spain), Visual Optics and Biophotonics Lab. (Spain)
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SimVis Gekko is a novel see-through binocular visual simulator that is based on liquid-membrane tunable lenses (TLs) projected onto the pupil of the eye using a twisted miniaturized 4-f system. Following a temporal multiplexing approach that introduces periodic defocus variations in optical power at 50Hz, the TL generates multifocal images on the retina of the observer, that look static. In this study, the image quality of different tentative designs of SimVis Gekko was evaluated for different optical powers. The full optical system of SimVis Gekko was computer-simulated to get the spot size, prismatic shift, angular magnification and field curvature up to 20º of the field of view. An image quality bench was developed to capture and process images through the SimVis Gekko simulator. The system comprises a grayscale camera and a 19-mm focal-length lens with an adjustable diaphragm. A high-resolution screen was placed at one meter with two different targets: (1) a checkerboard, imaged through a 1-mm diaphragm, to measure optical quality, prismatic shift, magnification, and optical distortion; (2) a binary noise, imaged through a 5-mm diaphragm, used to measure the local field curvature and image quality. Images were obtained from 1 to 3D of the TL and automatically analyzed. Theoretical simulations and experimental measurements showed good agreement. Magnification and curvature were the major differences across designs. The last version measured was free of optical distortions with a central curvature-free area with high optical quality. The developed system could guide the assembly and fine adjustment of active afocal optical systems.
Optomechanical Design II
Session Chair: Laurent Mazuray, Airbus Defence and Space (France)
11871-25
Author(s): Bruno J. Le Garrec, LASYEX s.r.o (Czech Republic)
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A telescopic zoom system made of three spherical mirrors has been designed for the purpose of electron acceleration with lasers. Its design follows the general arrangement for inverse cassegrainian systems described by Rosin. Following a general algebraic theory based on first and third order equations, it is possible to find a system corrected for spherical aberration, coma and astigmatism such that a collimated input beam will be focused to a perfect focal spot like in the Schwarzschild system. We will show that apart from the afocal solution, it is possible to get a continuous range of focal lengths when translating the second mirror (i.e. the overall dimension of the system does not change) . When changing the distance between the two first mirrors by a value equal to 20% of the focal length of the second mirror while keeping first and third mirrors fixed, we can obtain a focal excursion of the system from 6 m to 25 m for a 1-m translation of the second mirror. When dealing with on-axis mirrors, we will get a central obscuration and the next step will be to go off-axis such that no obscuration will occult the beam propagation. Moreover our laser beams are fairly well collimated with a residual divergence much less than 100 microradians which means that we are not considering any field of view like it is for astronomical systems. Finally we are currently building a mock-up of the system at a reduced scale first as a proof-of-principle and second to work on the alignment of the 3-mirror zoom. Results with residual aberrations in the final focal spot will be shown and discussed at the conference.
11871-28
Author(s): Wioletta Trzpil, Roman Rousseau, Diba Ayache, Nicolas Maurin, Aurore Vicet, Michael Bahriz, Institut d'Électronique et des Systèmes (France)
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Gas sensing find tremendous applications in various fields like medicine, air quality, food processing or security and defence. The main challenge in industry is to create an integrated and compact sensor while maintaining its performance and power consumption. Photoacoustic spectroscopy (PAS) gains particular interest in this field due to its excellent selectivity while maintaining compactness. In tunable laser diode absorption spectroscopy (TDLS) the signal is proportional to optical path. Sensitivity in photoacoustic spectroscopy is proportional to the power of the laser, which allows to keep a good sensitivity even with small gas cells. The use of mechanical resonator with high quality factor allows improving the signal-to-noise ratio and avoid the use of an acoustic chamber. Micro-electro mechanical systems (MEMS) fabricated in silicon technology remain a reasonable choice to realize a compact and integrated sensor, including laser source and electronics. We propose a capacitive transduction method, which can be easily integrated, compact and highly sensitive. Due to the multi-physics problem, time and financial contains, a theoretical model seems to be a first step towards sensor performance improvement. We propose an analytical model for a new concept of photoacoustic gas sensing using capacitive transduction mechanism. The model was reinforced with computational methods implemented in Python programming environment. The study was carried out using silicon cantilever as a model, which brings an opportunity to obtain an analytical solution for all physical parameters. The goal of this research stands maximization of electrical signal output and signal-to-noise (SNR) ratio. Conducted study provides a solution to retrieve a cantilever dimensions and frequency for integrated compact gas sensor. Beyond optimization, the model provides a comprehensive tool to understand mechanisms of sensor working principles and therefore stands as a tool allowing a mechanical resonator to be developed with a more complex geometry and/or different transduction mechanism.
Modelling and Simulation II
Session Chair: James Babington, Thales Optronics Ltd. (United Kingdom)
11871-31
Author(s): Richard Pfisterer, Photon Engineering LLC (United States); Neil Barrett, Tom Davies, CBS Europe (Ireland)
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Integrating spheres are commonly used in aerospace and laboratory applications as stable reference calibration sources. Even with models containing simple geometries, tracing enough rays in order to achieve statistically converged output radiance distributions can be prohibitively time consuming unless the modeling is approached correctly. In this paper, we discuss the use of very high scatter level Monte Carlo raytracing to model the performance of an integrating sphere that includes the specular and scatter properties of the interior surface, distribution(s) of the light source(s) and the effects of misalignments. We also demonstrate the use of GPU ray tracing to dramatically shorten the analysis iteration cycle, leading to faster product development.
Detectors and Microscopy
Session Chair: Ulrike Fuchs, asphericon GmbH (Germany)
11871-35
Author(s): Felix Bardonnet, Axel Crocherie, Marios Barlas, STMicroelectronics S.A. (France); Quentin Abadie, CEA-LETI-DOPT (France); Clemence Jamin-Mornet, CEA-LETI (France)
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Due to their low-cost fabrication process and high efficiency, silicon-based Complementary Metal Oxide Semiconductor (CMOS) image sensors are the reference in term of detection in the visible range. However, their optical performances are toughly degraded in the Near Infrared (NIR). For such wavelengths, Silicon has a small absorption coefficient, leading to a very poor Quantum Efficiency (QE). A solution to improve it is to implement structures like pyramids that are etched in the Silicon layer. This will lead to diffraction inside the photodiode, enhancing the light path and therefore the absorption. Using Finite Difference Time Domain (FDTD) simulations, we demonstrated a huge QE enhancement at 940nm on real pixels, by implementing this kind of diffractive structures and we finally confirmed these results by characterizations. We obtained QE values up to 47% at 940nm for our 3.2µm pixel, corresponding to a gain of 2 comparing to a pixel without any diffractive structures. We also measured the Modulation Transfer Function (MTF), to evaluate how this figure of merit is impacted by the addition of these structures. As expected, the MTF was degraded when we added these diffractive patterns but were still high looking at the values. We indeed demonstrated MTF values going up to 0.55 at Nyquist/2 frequency and 0.35 at Nyquist frequency. Looking not only at QE values but also at MTF ones, these are very promising results that could be used in many different NIR applications like face recognition, Light Detection and Ranging (LIDAR) or AR/VR.
11871-36
Author(s): Ganyu Chen, Yanbo Sun, Nanchang Normal Univ. (China); Xianlin Song, Nanchang Univ. (China)
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In order to eliminate the influence of Airy-beam sidelobe on photoacoustic microscopy and improve the resolution of imaging results, we use Lucy-Richardson Algorithm to deblur the Airy-beam photoacoustic microscopy. Due to its insensitivity to noise, Lucy-Richardson Algorithm is widely used in microscopy to deblur image in biological field. Lucy-Richardson Algorithm can deconvolution fuzzy images based on PSF, so as to restore fuzzy images. In this paper, after scanning and imaging of tilted vessel, the original imaging results were deconvolution. After five times of iteration of deconvolution of the original image, the image resolution is improved and clearer. This experiment proves that the Lucy-Richardson Algorithm can effectively improve the imaging system of Airy-beam photoacoustic microscopy and remove the influence of the sidelobe of Airy-beam.
11871-37
Author(s): Zhihui Li, XiongJun Cao, Xianlin Song, Nanchang Univ. (China)
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The photoacoustic microscopy combines the advantages of optical imaging and ultrasound imaging, with natural three-dimensional imaging capabilities. With the continuous development of imaging technology, photoacoustic microscopy has huge application prospects and development potential in many biomedical research fields, and it is supposed to become an increasingly attractive medical imaging method in the future. However, photoacoustic microscopy is still faced with many challenges, such as limited depth of field. In this paper, the traditional Laplacian pyramid fusion is proposed to extend the depth of field of three-dimensional photoacoustic microscopy, which effectively realizes large-scale, high-resolution imaging. It means that without changing the hardware layout of the imaging system, the purpose of extending the depth of field can be achieved with the aid of algorithms. To a certain extent, the contradiction between imaging speed and imaging range in large-scale, high-resolution imaging is resolved. Complete structure imaging is also of great significance for improving the accuracy of disease diagnosis. It provides convenience for the study of short-term dynamic response to physiological and pathological processes.
Poster Session
11871-9
Author(s): Alexander Terentyev, Kazan National Research Technical Univ. named after A. N. Tupolev - KAI (Russian Federation); Eduard R. Muslimov, ASTRON (Netherlands); Nadezhda K. Pavlycheva, Kazan National Research Technical Univ. named after A. N. Tupolev - KAI (Russian Federation)
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Design of an optical system implies definition of its’ parameters including both continuous and discrete variables. As the working spectral range expands and requirements to the systems’ aperture and image quality increase, the efficiency of existing algorithms for mixed-variables optimization become insufficient. In addition, the standard optimization tools do not provide all the necessary control and customization options. In the present paper we consider a custom optimization tool to perform a global search in mixed variables. It is based on the method of global optimization with selective averaging of variables. A positive selectivity coefficient is introduced into a positive decreasing functional kernel. With increase of the coefficient the averaging provides convergence of the target discrete variables to the optimal solution. We propose a custom optimization tool implementing this method and apply it for optimization of an f/1.5 objective lens working in the 0.9-1.7 μm domain with the field of view of 16 deg. The analysis shows that the new method allows to decrease the aberrations by factor of 2 when re-optimizing for the new working spectral range. In comparison with a direct glass model optimization with standard damped least squares algorithm our approach provides up to 1.26 gain in terms of the spot size. In comparison with the standard Hammer optimization tool it returns slightly lower image quality but shows afaster and more determinate convergence and also provides a much better control over the optimization process.
11871-14
Author(s): Eduard R. Muslimov, ASTRON (Netherlands); Nadezhda K. Pavlycheva, Ilya Guskov, Damir M. Akhmetov, Danila Yu. Kharitonov, Kazan National Research Technical Univ. named after A. N. Tupolev - KAI (Russian Federation)
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Aberration-corrected holographic gratings are widely used in spectral instruments. They allow to achieve highresolution and uniformly distributed diffraction efficiency as well as to combine several functions in a single opticalelement. However, their performance is limited. In particular, when the optical system has a large aperture thehologram replay conditions vary significantly across its’ surface. Due to this variation the hologram aberrationproperties and its efficiency change locally thus leading to decrease of the resolution and efficiency of the entiresystem. In the present research we consider a composite volume phase holographic optical element used as adisperser in a spectrograph design. Such an optical element represent a hologram recorded by stitching of severalelementary fields or zones. The refraction index modulation depth, the fringes tilt and the hologram spatialfrequency may vary locally in each of the elementary fields to match the changing reconstruction conditions.This approach allows to implement a better aberrations correction and to maximize the overall diffractionefficiency. We demonstrate an exemplary spectrograph design with a composite hologram for the visible rangeof 400-800 nm. It is shown, that in the design as fast as f/2.1 the maximum aberrations can be decreased byfactor of 1.19 and 2 in the X and Y directions, respectively, while the average diffraction efficiency increases by 15.6% at shorter wavelenghts. We continue the study by investigation of the composite hologram technologicalfeasibility and demonstrate that it can be recorded with a standard precision of the moving sources positioning,achievable stroke of the auxiliary deformable mirror and reasonably high accuracy of the photosensitive layer’s parameters.
11871-40
Author(s): Andras Cserteg, Kornel Jahn, Furukawa Electric Institute of Technology Ltd. (Hungary); Abel Mihaly Nagy, Budapest Univ. of Technology and Economics (Hungary); Kazuya Nagashima, Yozo Ishikawa, Furukawa Electric Co., Ltd. (Japan)
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Digital twin of a test assembly setup was developed to simulate the different steps of the alignment sequence of a coupling system. Furthermore, a software framework was created that can control both the assembly setup and the simulation engine. According to the tests, the simulated results correlate well with the experimental data, even under different environmental conditions, such as the presence of background noise. This approach can enhance the development of assembly sequences for different kind of micro-optics modules.
11871-43
Author(s): Jorge D. Alvarado-Martínez, Fermín Salomón S. Granados-Agustín, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico); Sergio Vázquez y Montiel, Univ. Interserrana del Estado de Puebla Ahuacatlán (Mexico); Alejandro Cornejo-Rodríguez, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
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In recent years, with technological advances, head-mounted display systems (HMDs) for virtual reality (VR) and augmented reality (AR) have been adopted for their applications in the military, government, education, training, medical visualization, aerospace, entertainment industries, and tourism. For this reason, a compact and light HMD but without sacrificing their performance is necessary. In this paper, the optical design of a lightweight and compact head-mounted display (HMD) system is proposed. We use an off-axis three-mirror system (OTS) with freeform surfaces for the correction of the aberrations and obtain a wide field of view (FOV), a compact structure with an exit pupil size over 7 mm and eye relief of 25 mm.
11871-48
Author(s): Stepan Ivanov, SAMSUNG R&D Institute Russia (Russian Federation); Kyuhwan Choi, Samsung Electronics (Korea, Republic of); Morozov Alexander, Samsung R&D Institute Russia (Russian Federation)
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Currently, in the field of optical design, there is great interest in assessing the complexity of an optical system prior to its actual design. In this paper, we propose a method that can estimate complexity by predicting the number of optical surfaces in a lens required to achieve diffraction-limited image quality. We show that it is sufficient to select the proper number of pupil points, field, and wavelength range to estimate aberration values at the design stage. Each control point corresponds to a ray passing through the optical system. The coordinates of the intersection of the input ray with the image plane are a function of the input ray and the parameters of the optical system. Thus, we can construct a system of equations from the functions of each control point. A solution exists when the number of variables (design parameters) is equal to the number of equations (control points). The basic idea is to determine the required number of control points of the field, pupil, and wavelength range, which gives us the number of design parameters. We have plotted empirical diagram for common combinations of focal length (F'), F-number (F#), field-of-view (FOV), and wavelength range. This information can be used to determine the desired number of control points and therefore to assess the complexity of the optical system being designed. Taking into account the geometric constraints and the variety of optical materials, the result of this method cannot be final, but it can be considered as a preliminary estimate of the complexity of the optical system.
Conference Chair
Airbus Defence and Space (France)
Conference Chair
asphericon GmbH (Germany)
Conference Chair
Thales Optronics Ltd. (United Kingdom)
Program Committee
Nathalie Blanchard
INO (Canada)
Program Committee
ASE Optics Europe (Spain)
Program Committee
TNO (Netherlands)
Program Committee
Eric Herman
Zygo Corporation (United States)
Program Committee
Leonardo (Italy)
Program Committee
Paolo Laporta
Politecnico di Milano (Italy)
Program Committee
Lab. Hubert Curien (France)
Program Committee
ScotOptix (Switzerland)
Program Committee
Carl Zeiss AG (Germany)
Program Committee
ONERA (France)
Program Committee
Univ. of Rochester (United States)
Program Committee
Elisabetta Rugi Grond
Thales Alenia Space Switzerland (Switzerland)
Program Committee
Leonardo (Italy)
Program Committee
Univ. Laval (Canada)
Program Committee
Qioptiq Ltd. (United Kingdom)
Program Committee
Riyo-LLC (United States)
Program Committee
Univ. Autònoma de Barcelona (Spain)
Additional Information