The arrival of ChatGPT, Google Bard, and other highly advanced artificial intelligence model show us just how brilliantly tasks can be reproduced by those engines. So, it's legitimate to wonder how our field (or any fields) might be affected in the future. We've already seen the beginnings of the possibilities, notably with LensNet [1], which provides optical designers with starting points for common cases; we can also study a solution space of certain type of lenses using deep learning [2]; and more recently, papers on the use of deep learning to simulate the entire chain of an optical system from object to final image processing, including tasks such as recognition. These latest end-to-end simulations have shown that in some cases, it is even necessary to redefine the optical optimization criteria to maximize certain computer tasks. In short, the computer doesn't necessarily need a good image in terms of MTF to perform its task. In this context, how the future will be affected or enhanced by these new AI approaches. In this presentation, I will first give a brief history of how AI has impacted optical system design since 40 years. Then I will use examples to discuss the extraordinary acceleration in works over the past 5 years, the choices that have or haven't been made, and the importance of having access to source code from publications. Finally, I will conclude with some thoughts on what may or may not lie ahead, and how we can introduce these new technologies into the training of future optical system designers. [1] Geoffroi Côté, Jean-François Lalonde, and Simon Thibault, "Deep learning-enabled framework for automatic lens design starting point generation," Opt. Express 29, 3841-3854 (2021). [2] Geoffroi Côté, Yueqian Zhang, Christoph Menke, Jean-François Lalonde, and Simon Thibault, "Inferring the solution space of microscope objective lenses using deep learning," Opt. Express 30, 6531-6545 (2022).

Developing an optical system from scratch involves many tasks and activities. From the design step to the delivery of the product, anything can lead to (mostly bad) surprises. Complex specifications, very challenging requirements, difficult technical choices, frightening tests or after-shipping non-compliance... the path to a good product is paved with many traps. This paper will present some of these issues, along with the solutions found to mitigate them, that occurred on the Spectral Separation Assembly, a sub-system of the Flexible Combined Imager, the main imaging instrument of the Meteosat Third Generation mission.

With the STAR Module, Ansys Zemax OpticStudio gains a built-on STOP Analysis tool which allows the user to load, visualize and numerically fit FEA Datasets from any FEA Solution onto the optical system inside Ansys Zemax OpticStudio and utilize the whole optical analysis tool range to assess the influence of thermal and structural loads on the optical performance. Join Flurin Herren, Optomechanical Engineer at Ansys Zemax, for a presentation which will outline the design process of a low-orbit telescope system and utilize the STAR Module to execute a full STOP Analysis workflow, considering the influence of thermal and structural loads on mechanical and optical components.

The Korea Astronomy and Space Science Institute (KASI) is developing GrainCams as a candidate payload for NASA's Commercial Lunar Payload Services (CLPS) mission. GrainCams consists of two cameras designed for scientific research on the lunar regolith and levitating particulates. One of them is LevCam, which observes the motion of levitating dust over the lunar surface. The other is SurfCam, a camera intended for observing the uppermost regolith on the lunar surface. The purpose of SurfCam is to get knowledge of the regolith on the lunar surface and obtain 3D images of the micro-structures through image processing with a micro-lens array (MLA). SurfCam consists of 1 cover window, 12 spherical lenses, and MLA. All optics use space-qualified glass material to carry out a one-lunar-day mission on the moon. Optical and mechanical designs have been developed so far, and an analysis of how stray light affects the overall system has been conducted. In this paper, I will describe the analysis of ghosting and scattering effects in SurfCam through stray light analysis.

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. The final optomechanical configuration, its performance and straylight behavior are described in this paper.

Current optical design concepts and methods heavily rely on ray tracing and optimization algorithms. These methods often require extensive expertise, good intuition, and involve iterative trial-and-error workflows. We propose a novel approach that directly generates promising initial designs based on the application- and user-specific requirements and constraints. Our newly developed 'First Time Right' (FTR)-based design tool automatically calculates all optical surface coefficients to minimize image blurring across all aberration orders. Importantly, it also incorporates any imposed practical constraints, such as stop position, length, spacings, distortion, telecentricity or back focal length restrictions. To further enhance our methodology, we have combined our FTR-based Start Lens Generator with PanDao, a software that models fabrication chains based on provided design data. This integration aims to minimize both manufacturing costs and risks. We have evaluated and refined several real-world lens design examples, resulting in excellent alternative designs that maintain equivalent optical performance while typically achieving less stringent requirements for tolerances and significant reductions in overall production costs.

A new method for glass substitution during the lens design has been developed. Exploring existing longitudinal aberration contributions, the new method uses sensitivity analysis to find optimal optical glass constants (refractive index, Abbe number, and relative partial dispersion) for certain optical system elements. A case study introducing the glass substitution method to the optical system design is described. It is shown that the new approach provides step-by-step improvements in the optical system’s longitudinal aberration correction. The current limitations of the method are also described.

Natural Guide Star (NGS) wavefront sensors (WFS) play a crucial role in multi-conjugate adaptive optics systems by detecting low-order aberrations that laser guide stars cannot measure. In the framework of MAVIS, we plan to use the light from three NGSs to correct the tip-tilt and low-order errors of the wavefront. In this work, we conduct the analysis of the distortions caused by mid-spatial frequency figure errors of the optical surfaces in the NGS WFS channel of the adaptive optics module of MAVIS. These distortions, stemming from component imperfections, can significantly impact wavefront measurements and, consequently, the plate scale in the image plane of the entire instrument. We analyse their influence on the plate scale variations during tracking. Our study quantifies the effect, shedding light on the impact of non-common path distortions between the NGS WFS and the scientific instruments on plate scale variations, ultimately contributing to optimising the MAVIS performance.

CMOS image sensor cameras are widely used in various applications, across industries such as aerospace and defense, automotive, and consumer electronics. With the emergence of high-resolution cameras, obtaining the best image quality is becoming a must-have requirement. There is a growing need to design and optimize each camera component considering image quality of the full system in the targeted application environment. Accurate modeling of such components can be challenging due to multiscale structures going from nanoscale photonics to macroscale optics. To mitigate the modeling problem, Ansys provides ray and wave optics tools to simulate and optimize the design of the different modules of the camera system (lens imaging system, nanoscale pixel structure, digital processing) in a virtual environment with different illuminations, scenes, and scenarios, and evaluate the quality of the complete camera system. The lens system is designed with the optical design software Ansys Zemax OpticStudio. Then, an optical Reduced Order Model (ROM) of this lens system is exported to Ansys Speos, a ray tracing software embedded in a 3D CAD environment that provides fast yet accurate simulation while accounting for environmental conditions, including artificial and natural light sources. In parallel, Ansys Lumerical provides the quantum efficiency of the sensor by combining FDTD, a fully vectorial 3D electromagnetic solver, for the light absorption and CHARGE, a 3D charge transport solver, for the probability of collection of photogenerated charges. Light exposure from the 3D scene through the lens system onto the sensor is combined with the quantum efficiency of the sensor to generate raw images. Finally, digital processing allows the generation of the final image. The ROM has been validated by comparing it against full lens system simulations. The MTF50 differs by less than 10% between the models, and the ROM offers between 10 and 100 times speed performance while maintaining accuracy.

Tolerance analysis is a critical part of the optical design process because it helps predict system real performance, after manufacturing and assembly. To obtain reliable predictions, it is mandatory to use realistic optomechanical models. INO developed Comet software, a powerful standalone application for realistic optical tolerancing analysis. A previous paper demonstrates how a better modeling helps avoid the production of overly expensive optical systems with excellent performances, or on the other hand, the production of inexpensive optical systems with unexpectedly erratic performances. This article presents the methodology used to find the best centering method for an infrared dual-band objective. INO’s Comet standalone software application is used to perform the optomechanical tolerance analysis and computes the perturbations to be applied in the optical tolerance analysis. It will be demonstrated how Comet is quick and easy to use for comparing several centering concepts, helping to find the best trade-off between optical performances and ease of manufacturing. The studied infrared dual-band lens requires almost diffraction limited performances to fulfill the needs of the foreseen application. Therefore, two accurate centering techniques are considered: the active alignment and the QuickCTR autocentering technique. The active alignment is the most accurate method for centering optical elements, but requires expensive instrumentation, human manipulation, and cure time for the adhesive. The QuickCTR auto-centering techniques are almost as accurate as the active alignment but requires a fraction of the effort for centering, thus is less expensive to implement. The presented methodology will show how to get the best compromise by using both techniques.

To properly account for imperfections in fabrication of lenses and mechanics as well as optics alignment limitations, it is necessary to run a tolerance analysis during the optical design process. But it is often unclear what level of detail the tolerance model necessitates to accurately predict the variation in performance, and there are consequences of time and money for both overly optimistic and overly pessimistic designs. In this work, we compare the assembly results of a precision microscope objective with an initially overly pessimistic tolerance analysis and develop an improved tolerance model in agreement with the performance of as-built systems. The system is analyzed in two industry-standard optical design software packages, Zemax and CODE V, and the results are compared with each other and with assembly data. The Zemax Monte Carlo analysis agrees with as-built data by including manufacturing and assembly tolerance statistics as well as by modelling compensation procedures used in the lab. Analyses in CODE V’s TOR and Monte Carlo yield consistently similar results to each other but are more pessimistic than the Zemax analysis. All three methods are found in agreement by reducing the irregularity tolerance on CODE V analyses to reflect the software’s differing tolerance definitions. Although much faster, CODE V’s TOR is unable to model complex compensation procedures, suggesting that a preliminary analysis in TOR should be followed by a more thorough Monte Carlo analysis to avoid overspecification of components. Several aspects of the tolerance model developed here are generalizable to other systems.

Aperture and volume constraints can impact the design form of a telescope. While freeform optics may positively impact volume and weight, opting for a conventional approach may still be the optimal choice. This paper will include a design for an Earth-observing telescope, along with an exploration of the methodology and trade-offs associated with various design forms investigated throughout the design process.

The adoption of freeform optics by designers and manufacturers has increased in recent years. With the increase of flexibility, a freeform surface can bring a system, it also brings more sensitivities. To effectively control these sensitivities during integration, the tolerancing needs to incorporate the limits of the metrology device for the tolerance operand under test. Understanding a vendor’s manufacturing and metrology capabilities is critical to designing and tolerancing a freeform surface that uses its physical features to aid in integration. Interfacing with a vendor early in the design process may improve manufacturing timelines due to the alignment of the freeform definition with the available metrology. Favorable freeform definitions will be reviewed along with tolerancing and specification recommendations.

We present a new approach for the tolerancing of correlated optical systems. These systems consist of at least two optical channels, which are linked together. To represent the correlations e.g., for compensators correctly in the tolerancing procedure, tabulated pseudo random numbers are used. This leads to efficient tolerancing and accurate results.

Ghost images refer to unwanted secondary images or reflections that appear alongside the primary image, causing interference or reducing image quality. These ghost images are caused by multiple reflections of in-field imaging rays within the optical system. We have developed a methodology for comprehensive modeling and analysis of ghost images produced within a catadioptric multi-spectral imaging systems. Instead of characterising these ghosts as mere points of light, we conducted a detailed qualitative and quantitative examination of the ghost reflections. We identify cross-talk ghost as a significant issue, even with low surface reflection coefficients. By identifying major contributors, the study enables the formulation of robust mitigation strategies. Our methodology includes generating ghost layouts, identifying primary contributors, and precisely quantifying the flux stemming from these ghost reflections. Furthermore, we introduced multiple strategies for reducing ghost reflections, culminating in the design of a Ghost Blocker Plate engineered to effectively counteract ghost reflections. A series of meticulously planned experiments was conducted to validate our developed methodology. As a result, we successfully demonstrated a substantial reduction in ghost reflections within an optical system, reducing them from an initial level of 23% to less than 1%.

Minimizing glare and ghost images in an optical system through stray light control is a significant percentage of the system’s design time and cost. Fresnel reflections that cause stray light are often among the worst offenders, and companies rely on optical coatings to reduce the reflections' impact and increase the signal-to-noise ratio (SNR). To facilitate component-level stray light analysis and reduce cost by coating only needed surfaces, we have created a stand-alone tool that uses the OpticStudio Application Programming Interface (API ) to analyze the stray light optical paths and identify the contribution of each component to the noise. Once the contributing surfaces are identified, coatings can be applied only to the worst offenders until the desired SNR is achieved. This process reduces the analysis time and helps to reduce costs compared to coating all the surfaces in the optical system. Use cases and SNR analysis to validate the tool will be presented.

Stray light analysis is essential for the design of high-quality optical systems, to ensure that unwanted light reaching the sensor is minimized, and artifacts that degrade optical performance - such as lens flare - are mitigated. This article introduces a system-level approach for stray light analysis using Ansys Optics simulation tools, considering stray light from both optical and non-optical components. The article illustrates how these tools can be integrated with Ansys optiSLang for automated exploration and design optimization. The practical camera use-case highlights a seamless data exchange between Ansys Optics simulation tools. It employs a range of intuitive features, from Ansys Zemax OpticStudio's sequential ray tracing, extending to Ansys Speos ray path analysis, while leveraging HPC and Cloud Computing. The combined capabilities offer an efficient solution, streamlining collaboration and enabling optimized optical system designs.

The Copernicus Land Surface Temperature Monitoring (LSTM) mission will perform spatial high temporal observations of land-surface in visible, near and thermal infrared bands. The LSTM mission requires very stringent straylight performances to meet the absolute radiometric accuracy, leading to straylight correction processing need. To get accurate correction, strong efforts are to be made to minimize the straylight level by optical design, over the mission wide spectral range. The LSTM instrument is currently under development at Airbus Defence and Space in Toulouse. The optical design is based on a dual freeform Three-Mirror Anastigmat telescope, including two-stages spectral filtering at intermediate and detector focal planes. The design optimization is mainly driven by straylight rejection, either in a geometrical or in a spectral way. A complete straylight model of the instrument is developed, including optics and mechanics, with their respective coatings and scattering models, using non-sequential raytracing software. We perform ghosts and scatter simulations in the frame of instrument PDR, taking into account multispectral effects. The straylight simulations include very detailed features, such as introduction of coating listels or computation of ghost spectrum. The methodology used for baffle optimization is described, especially slit masks implemented on spectral filter subassemblies, at each focal plane. A parametric study is performed, to get an optimized parameters set for each mask, ensuring meeting straylight performances, and taking into account footprint tolerancing, manufacturing and alignment.

Since the development of the first achromatic lenses back in the 18th century, dispersion models have been constant companions of optical designers. Various alternatives and extensions to the classical Abbe number and partial dispersion model have been proposed over the years, with the goal of making first- and higher order analysis and correction easier accessible. Hoogland’s reformulation of the classical quantities allowed to visually select glasses and read optical powers for an apochromatic lens from a diagram, and Buchdahl dispersion coefficients have been used as basis for similar work in the infrared spectrum. In both cases however, model parameters must be tuned to arrive at the desired representation. Here we present a model-free approach using principal component analysis of normalized refractive index data at the system wavelengths. We show how it can be applied to understand simultaneously both the dispersion properties and color correction capabilities of a selection of glasses in any part of the optical spectrum, and how to derive favorable glass combinations for apochromatic and superapochromatic lenses including a prediction of residual color.

Hybrid diffractive lenses are an enabling technology that allow the shaping and control of wavefronts by precisely controlled zone structures, a coherent version of a standard Fresnel lens. They are extremely useful in the medium and long wave infrared spectral regions for performing colour correction, where traditional cemented doublets (that are used in the visible region) are not an option. These surface structures are often modelled not as an actual physical structure, but in a way that treats the surface fictitiously as a phase function on the surface. This makes some results dubious and provides a substantial difficulty in assessing and specifying tolerances. In the current presentation, we review a more physical model based on the ideas of zone decomposition and then show how this may be applied to advantage for multi-order diffractive lenses (where the blaze structure is now an integer multiple of the basic step height). The zone decomposition view is ideal for understanding the diffractive structure on a lens surface. In particular, it allows one to view diffraction efficiency and colour correction in a different manner. With this standpoint, one sees how interpolation takes place from a standard diffractive surface all the way up to purely refractive Fresnel lens. The multi-order diffractive surface sits between these exhibiting both coherence across different zones but also the onset of incoherence, thereby returning to a surface with only refractive properties.

Recently the first automotive vehicles with micro-optical headlights entered the market as series production models. Besides aesthetics, multi aperture micro-optics bring the advantage of a reduced axial length of the system due to the much shorter focal length of each channel. However, the currently implemented low-beam systems suffer from low transmission and notable cost for the micro-optics elements. Both problems can be traced back to the buried micro-slides within the micro lens arrays, (MLA) which shape the distribution. To overcome these issues, we developed a micro-optical solution for a low-beam without mask layers, thereby significantly increasing transmission to a very competitive level and enabling more cost-effective manufacturing processes. Our design follows the general principle of a fly’s eye condenser (FEC) but comprises of a multitude of differently shaped lenslets, which form the beam collectively. The design process includes the generation of the overall distribution as well as detailed features such as the sharp and specially shaped cut-off and a smooth distribution within the beam. Particular effort is necessary to control stray light which is caused by imperfect manufacturing of the MLAs. A first LED-illuminated demonstrator showed that the shape and the required sharpness of the cut-off can be achieved even without the use of absorbing masks with a single optical module. Stray light control and fine tuning of the distribution makes it possible to manufacture a maskless polymer-on-glass micro-optical component and generate a beam pattern in accordance with UNECE safety regulations.

Performance and reliability requirements for modern optical systems dictate that they can no longer be simulated in isolation without reference to external and environmental factors which can adversely impact image quality. Simultaneously, advances in multi-physics simulation techniques have made it possible to couple the impacts of, for example, thermal changes and structural stresses to optical analysis to better predict performance in operational conditions. Applications where light propagates through a fluid surrounding or within an optical system present a particular simulation challenge in this regard, and one that requires new simulation techniques. In the near-field, variations in pressure, temperature, and density of the fluid give rise to corresponding variations in refractive index that will, in turn, induce optical aberrations in a transmitted wavefront. These aberrations can lead to degraded image quality and line-of-sight errors. Accurate and robust analysis of such effects necessitates the coupling of computational fluid dynamics (CFD), for simulation of turbulent flow, shock waves, etc. with ray tracing to compute key optical metrics. Furthermore, this analysis can be combined with far-field atmospheric effects, including emissivity, absorption, scattering, refraction, to build a comprehensive picture of system performance. The ability to perform multi-physics simulations early in the design process provides the opportunity to develop strategies to identify and mitigate negative performance drivers. We present a solution to model the effects of light propagation through optical fluids accurately and combine this with analysis of structural and thermal effects. This solution will be demonstrated in use cases including electro-optic infrared airborne systems.

For the design of well corrected optical systems with a certain spectral bandwidth, it is often not sufficient to only control axial and lateral color, but also chromatic variations of the fourth order wave aberrations or Seidel coefficients need to be considered. This has already been studied in detail in the literature by Berner. We propose a different approach to calculate the induced surface contributions to chromatic variations of the Seidel coefficients, which is based on the principles of stop and object shift. This offers a different perspective that might be helpful for optical designers. Furthermore, it is demonstrated how this approach generalizes to other cases of tolerance sensitivities of rotationally symmetric systems.

Optimizing freeform systems can encounter convergence difficulties due to the many degrees of freedom that these surfaces bring to optical systems. Moreover, the description of these freeform surfaces in a polynomial basis may impose prior knowledge on the shape of the surface. In this presentation, we will showcase a differential ray tracer with NURBS capabilities called FORMIDABLE. In contrast to available commercial optical design software, such as Zemax OpticStudio and Synopsys Code V, this library ican simulate and especially optimize Non-Uniform Rational B-Spline (NURBS) surfaces. The key advantage of NURBS lies in their ability to locally describe an optical surface, thereby minimizing preconceived notions about the surface shape, aside from the surface sampling determined by the density of the NURBS representation. The main drawback, however, is the significant increase in the degrees of freedom within the optical system, making the optimization of these surfaces a complex task with a conventional commercial optical design software. FORMIDABLE's implementation of differential ray-tracing capabilities allows faster convergence of systems described by many degrees of freedom and makes optimization with NURBS surfaces viable. The features of FORMIDABLE will first be described. Then its capabilities will be illustrated with the optimization of a classical non-reimaging Three-Mirror Anastigmat (TMA) by considering either a description of surfaces by NURBS or a description by the polynomial basis XY. Then, this optimized TMA will be compared with its equivalent optimized with Zemax OpticStudio. To enable this software comparison, we will use the same starting point and practically the same merit function. Standard metrics, such as Root Mean Square (RMS) spot size across the field of view (FOV) will be used to assess the imaging quality.

The use of a photon sieve (PS) structure has been suggested to design intracorneal implants with drainage holes and multifocal properties. In this study we present how the customization of the 3D hole profile allows designing an innovative implant for the correction of presbyopia. This new implant consists in a transparent PS with bevelled holes whose use in a bilateral mix-and-match approach can provide good visual acuity on an extended range of distance. This blazed photon sieve is also apodized, enabling the ratio between energy in distance and near vision to be controlled according to pupil size. In addition, the hole rings of the photon sieve are placed on the odd radii of the Fresnel rings to maximize the surface area of the photon sieve slopes for small pupils, thus providing near vision energy for all pupil sizes.

An Offner spectrometer with a freeform grating has been designed. The aim of the introduction of freeform technology on the spectrometer is to enhance the field of view of the instrument, while meeting specific performance requirements The Offner spectrometer comprises three concentric mirrors creating a telecentric imaging system, by introducing the freeform element, the spectrometer's layout is optimized without altering its fundamental structure. The design study started with a layout employing only standard optics, and the maximum operable field of view was investigated (51mm). The implementation of a freeform polynomial to the grating’s surface resulted into a significant expansion of the field of view, up to 58mm. The chosen polynomials for the description of the new surfaces are Zernike FRINGE sag up to the 21st order coefficients. During this phase, all variables of the layout are free to be changed, including all positioning variables. Performance benchmarks such as smile and keystone distortion, Modulation Transfer Function (MTF), and dispersion grating specifications are consistently taken under control during the design development. This study underscores the efficacy of freeform optics in pushing the boundaries of optical technology, with promising implications for imaging systems and optical instrumentation optimization. The successful application of freeform optics in this Offner spectrometer design exemplifies its potential for advancing optical engineering in various fields.

Space-based spectrometers are of high importance for Earth observation and greenhouse gas sensing. We present a novel freeform pushbroom imaging spectrometer, covering the visible (400 – 1100 nm), near-infrared (1100 – 1700 nm) and thermal (8 – 14 μm) wavelength range, showing a full field-of-view of 120°, while fitting within a single CubeSat Unit. The design is composed of a freeform 2-mirror telescope, followed by a freeform spectrometer unit. The freeform telescope guides the light to the spectrometer entrance slit, after which a collimating mirror is present, and the light is split to the 3 spectrometer channels. Each spectrometer channel focuses the light onto a 2D detector providing both spatial and spectral information. The visible spectrometer channel comprises a transmission diffraction grating followed by 2 freeform mirrors, enabling a nadir spatial resolution of 9.87 km and a spectral resolution of 5.18 nm. The near-infrared and thermal spectrometer each comprise a reflective diffraction grating and 2 freeform mirrors, featuring a nadir spatial resolution of 4.13 km and 9.31 km, and a spectral resolution of 2.74 nm and 48.27 nm, respectively. All mirrors are described using XY polynomials, up to the 4th order, enabling a close to diffraction-limited performance. Consequently, this design might benefit future space missions enabling an improved Earth observation and climate monitoring.

Planetary exploration missions generally impose high demands on both the imaging quality and the size-weight constraints of optical systems. Therefore, this paper proposes using curved detector in the design of a fast and wide-field off-axis freeform three-mirror optical system, aiming to achieve high imaging performance within a relatively small volume. Specifically, a freeform-shaped curved detector is considered in the off-axis system design, which ultimately enables the system reach a near diffraction limited image quality within 10-liter volume. The proposed design shows great potential for application in planetary exploration missions, making the higher performance imaging instruments feasible in the future missions.

ANSER Atmosphere (AT) is the second mission of INTA’s SmallSat constellation program. Its main objective is the study and monitoring of greenhouse gases, air quality and polar ozone by absorption spectroscopy. It is composed of a cluster of four CubeSats flying in formation, each of them comprised of 6U. The main payload of each CubeSat consists of a catadioptric telescope (1U) and a refractive spectrometer (2U) each of them working in a different spectral range from UV to SWIR. The optical design of the spectrometer, which spectrally disperses and analyses the energy collected by the telescope, is based on a reflective diffraction grating with a slit at the entrance. Due to the fact that this is an atmospheric observation mission and the precision required for the measurements, it is necessary to eliminate the polarization of the incoming light. For this reason, depolarizers have been included in the instrument design.

Metasurfaces is an emerging technology, poised to disrupt diverse application sectors of the optical industry, including AR/VR, Light imaging and Ranging (LiDAR) and optical design. With respect to conventional diffractive optical elements (DOE), Metasurfaces provide considerably higher scalability, larger field of view (FoV) and enhanced diffraction efficiencies (DE). In addition, their design flexibility allows for arbitrary intensity, phase and polarization far-field distribution. Most of the commercial imaging LiDAR devices rely on light scanning architectures that enforce compromising between FoV and frame rate. Splitting incident power to project a point-cloud of intensity distribution in the far-field, flash LiDAR systems can improve imaging speed, but at the expense of the imaging depth. To overcome these limitations, metasurfaces have been proposed as a good alternative to conventional LiDAR components, for both detection and illumination. However, further efforts in improving design, fabrication and characterization of those functionalized surfaces are still needed. Here, we demonstrate the advantage of design flow based on inverse design capability for the generation of a metasurface targeting advanced beam steering and arbitrary point-cloud illumination for 3D sensing. The development of metasurface-based projectors, able to generate arbitrary light distributions -beyond classical diffraction patterns- would open new LiDAR imaging capabilities with improved resolution and performances.

This conference presentation was prepared for SPIE Optical Systems Design, 2024.

This conference presentation was prepared for SPIE Optical Systems Design, 2024.

This conference presentation was prepared for SPIE Optical Systems Design, 2024.

The Copernicus Land Surface Temperature Monitoring, LSTM, mission will perform spatial high temporal observations of land-surface in visible, near-infrared and thermal infrared bands. LSTM payload includes a telescope feeding two optical paths: one for a visible imager (VIS) and a near-infrared imager (NIR), the other path for a thermal infrared imager (TIR). The VIS and NIR imagers contain specific freeform field lenses and shall be co-aligned with a drastic accuracy (typically +/- 5 μm). Since this co-alignment is performed before telescope availability, an on-ground testing bench (OGSE) is required to co-align VIS&NIR focal planes. This bench shall be able to emulate, field by field, the MTF performances of the LSTM telescope. OGSE main components are a spherical mirror, several beamsplitters, a deformable mirror and a wavefront sensor (WFS). The OGSE goal is to generate in closed loop representative wavefronts in VIS&NIR LSTM aperture stop plane. The particularity of this OGSE is that the output wavefront is far from being spherical since each VIS&NIR imagers field lens corrects a large WFE generated at LSTM telescope level. Furthermore, the wavefront changes significantly from one point of the field of view to another. Finally, and importantly, the OGSE needs to allow co-focussing of VNIR & SWIR detectors despite it does not illuminate both fields simultaneously. In order to simulate the OGSE achievable performances we simulate the deformable mirror on the optical design software (CodeV) with its active actuators as variable parameters.

Research and developments on thermal infrared zoom lenses over the last decade (2010 onwards) will be surveyed in this talk, with a special focus on mechanically compensated continuous zooms for cooled detectors. During the time period under consideration, SWaP (Size- Weight and Power) optimized optomechanical systems were realized, to compactly fit zoom imaging functionality in previously unconventional platforms such as UAVs (Unmanned Aerial Vehicles). Dual band zoom systems, imaging in both the Mid wave (MWIR) and Long Wave (LWIR) thermal regimes have been explored. There has been considerable research and development activity in the field of chalcogenide material technologies which open up design possibilities for broadband transmission applications (VIS through LWIR). The feasibility of zoom functions implemented via non-traditional elements such as metalenses, Alvarez lenses, deformable mirrors, and multi-layer Diffractive Optical Elements (MLDOE) have been demonstrated.

The field curvature has been a long-term problem optical designers had to deal with, to propose flat corrected field instruments. Combinations of highly aspherical optics, TMA configurations, achromatic doublets or field flatteners are often used to reach good optical quality across the image. Allowing designers to play with the parameters of the field’s shape is offering them a brand-new game field. The possibility of curving the CMOS sensors to fit curved/aspherical/freeform shapes of focal surfaces has been studied for the last 20 years and led today to different applications and prototypes. We present in this article 1/ the parameter studies we performed over a large set of optical designs showing the gain offered by this approach, 2/ the CMOS sensors curving process and performance over a large set of prototypes, 3/ Optical systems that have been produced with this technology and 4/ the roadmap related to the development of curved-sensors based instrumentation for astronomy with the CASTLE telescope project and physical sciences through the Auroral UV Imager program led by ESA, and the IMANCES project led by the Neurosciences Institute INT.

In this study, we present a miniaturized, tuneable light source achieved through the integration of a piezo-actuated Fabry-Pérot Interferometer (FPI) with a broadband light source. Our experimental setup combines the tuneable FPI with a white light source, allowing us to investigate the spectral properties of the emitted light under varying applied voltages. We develop and validate a theoretical model to analyze the optical performance of the system, focusing on parameters such as transmission and spectral resolution. We explore the impact of thickness variations in the coated multilayer structure on the achievable spectral resolution. To enhance the versatility of our miniaturized light source, we propose a novel configuration that combines six distinct FPI modules. Our findings contribute to the advancement of compact, broadband, tuneable light sources, with potential applications in various fields such as spectroscopy, imaging, and optical sensing.

Sentinel-4 is an imaging UVN (UV-VIS-NIR) spectrometer, developed by Airbus under ESA contract in the frame of the joint EU/ESA COPERNICUS program. The mission objective is the operational monitoring of trace gas concentrations for atmospheric chemistry and climate over Europe. Sentinel-4 will provide accurate measurements of key atmospheric constituents such as ozone, nitrogen dioxide, sulfur dioxide, methane, and aerosol properties. The instrument is composed of two dispersive spectrometers covering the spectral ranges of 305–500nm and 750–775nm and a common telescope which projects an image of the Earth onto the two slits. The instrument will be placed in a geostationary orbit, and a 3D spectral-spatial data-cube will be acquired thanks to the mirror scanning in East-West direction. The Telescope Spectrograph Assembly (TSA) represents the core of the optical system inside the Optical Instrument Module (OIM). It is composed of the telescope, the two spectrographs and the two Focal Plane Assemblies (FPAs) which need to be integrated and aligned into the supporting structure. After verification of the optical performance parameters, in operating conditions, the TSA is finally integrated in the OIM. The Instrument Proto Flight Model (PFM) was aligned in 2020 and after undergoing the Calibration and Characterization campaign in 2022 it was finally integrated onto the Meteosat Third Generation (MTG-S) platform next to the Infrared Sounder (IRS) instrument in 2023. This paper gives an overview of the Flight Model 2 (FM2) TSA integration and alignment activities performed at the Airbus premises in Ottobrunn, Germany, during the first half of 2023. It describes the alignment philosophy developed to meet the challenging optical requirements, including spectral resolution, ground spatial sampling distance and spatial coregistration between the two channels. The results of the optical tests, performed before and after transition from ambient laboratory conditions to the operating conditions reproduced in a thermal vacuum chamber, will be presented and compared to those of the PFM instrument.

Bessel beams, known for maintaining focus over long distances, find many applications in imaging, nonlinear optics and laser material processing. For these applications, generating sub-micrometer Bessel beams is essential, but requires complex optical systems. Traditional optical software, designed for ray tracing, are challenged for this task. Here we show how we can use optical software to create and optimize optical design to generate these unconventional beams. The research involves high numerical aperture systems, investigates the influence of polarization, and the use of diffractive optical elements. Numerical findings are compared to experimental results, highlighting the potential of software-assisted beam design for various applications.

Stock lenses are attractive components in optical system design, offering lower cost and ready availability when compared to custom lenses. However, the lack of effective (optimization) tools to design systems with stock lenses often leads to a manual, thus time-consuming and highly iterative design process with low success rate and clearly non-ideal results. In this work, we present an automatic optical design tool that uses only stock lenses from known suppliers to generate lens systems directly from the specifications and constraints given by the user, without requiring any nominal starting or reference design. To efficiently master this complex problem of selecting working stock lens combinations, our proposed tool makes use of the ‘First Time Right’ design method to generate constraint stock-based lens systems of both finite and infinite conjugate configurations from scratch. The method relies on Fermat’s principle and enables a highly systematic generation and very fast evaluation of arbitrary lens designs. This all-analytic approach makes the pre-selection and positioning of stock lenses highly efficient computationally. We will demonstrate and discuss the extensive and fast exploration of stock lens solutions offered by the stock lens-based design tool using several- practical lens design examples. These results clearly highlight the tool’s capabilities for streamlined stock lens-based system exploration and the cost-versus-performance analysis.

There has been a notable advance in detection systems during the last decades. On one hand, these advances allow the design of systems with higher resolution and better performance, but on the other hand, they are more sensitive to unwanted light. In infrared systems, Narcissus is one of the major problems of unwanted light to avoid. This problem is especially more difficult to control in zoom infrared systems, where there are a considerable number of zoom positions which must be carefully checked to analyze the presence of Narcissus. Usually, Narcissus can be eliminated using an offset non-uniformity correction (NUC) or One Point NUC (OPN). In order to be eliminated through this algorithm, it is necessary that the NITD of the system at all zoom positions is under certain level according to the detector sensitivity. But although the system can fulfill this requirement, we have found situations where Narcissus is highly sharp but still exhibiting low levels of NITD. This sharp Narcissus is not possible to eliminate through OPN. The sharp Narcissus was first found during measurement test and then reproduced through simulations in Zemax. These simulations allowed us to find the root cause of the sharp Narcissus. These findings trigger the need to establish solid requirements to avoid not only Narcissus under certain NITD values, but also focused Narcissus. In this paper we present Narcissus measurements and simulations results, pointing out the root cause for Narcissus, and potential solutions for this problem.

Future large-scale spaceborne optical instruments for Earth observation or astronomy will call for large primary mirrors with very challenging performance specifications. At design level, our work focuses on improving the integration of mechanical, thermal and optical analysis in efficient iterative loops, to quickly lock-in on mirror designs which simultaneously balance mechanical and thermal constraints. We rely on a new automatic mesher called PAMPA which quickly generates parametric models, and is iteratively called upon by an end-to-end automatic workflow to evaluate the mirrors’ performance.

This paper provides an accurate and simple simulation workflow for Structural, Thermal and Optical Performance (STOP) analysis on complex optical systems. Applying this workflow to a high-power laser system, we use Ansys Zemax OpticStudio for both optical design and wavefront analysis. Then Ansys Speos is used for optical heat load calculation on each component of the system. Finally, Ansys Mechanical is used to perform thermal and structural analysis, providing this information back to OpticStudio for wavefront error analysis and optical tolerancing. The workflow is fully automated thanks to Ansys System Coupling interface. Besides the ease of use, this workflow captures the impact of structural deformations and refractive index changes on the key performances of any optical system, accounting for opto-mechanical component contributions. The approach can be steady-state or transient.

Wood, with its exceptional characteristics of lightness and strength, presents notable technical possibilities in industry, as well as serving as a significant carbon sink for society. Nonetheless, the natural diversity of wood species, particularly in temperate areas, poses a challenge when attempting to assess associated mechanical properties and to anticipate widespread application in mass markets. The wood manufacturing community is therefore seeking to establish rapid and automated techniques to determine the characteristics of French wood species, focusing on wood of all grades. One such technique which has received much recent interest is based on the “tracheid effect” which provides information on the local orientation of wood fibres. However, this approach is not universally applicable to all types of wood, and the factors that impact the tracheid effect are still relatively understudied, relying on scattering models using Monte-Carlo simulations. ZEMAX OpticStudio@ANSYS (ZOS), a powerful optical design software suite, has a non-sequential module similar to Monte Carlo approaches and includes a CAD module for modelling complex structures. This presentation shows how the use of this software improves our understanding of the phenomena involved in the tracheid effect, and can enable a more thorough characterization of wood fibre orientations. We compare our models with experimental data from common wood species. In this way, we hope to improve the measurement of wood properties and optimize the use of secondary-grade wood in sectors such as construction, furniture and packaging.

The MMX Infrared Spectrometer (MIRS) is an imaging spectrometer aboard the MMX (Martian Moons eXploration) JAXA mission. MIRS was constructed at LESIA in collaboration with five other French laboratories, with the collaboration and financial support of CNES, and in close partnership with JAXA. MIRS will remotely provide near-infrared spectral maps of Phobos and Deimos, containing spectral features used to analyze surface composition. MIRS will also study the Martian atmosphere, focusing on spatial and temporal changes in clouds, dust, and water vapor. A span of three and a half years separates the initial optical design studies for this instrument and the ongoing final tests conducted under vacuum on MIRS PFM (Proto-Flight Model) at LESIA facilities. Many design and development choices were influenced by this limited lead time. This paper will describe the key stages in the optical architecture's evolution during the instrument's development, guided by a design-to-effectiveness philosophy. Following an overview of the mission, its objectives, and the optical requirements of the instrument, we will expose the trade-off between a dioptric and a catoptric design, resulting in a catadioptric design including four freeform mirrors, a plane-ruled grating, two lens assemblies, and a linear variable filter. Each optical subassembly will be detailed, presenting its primary as-built characteristics. The alignment tolerances and procedures will also be briefly explained. Lastly, the measured optical performances of MIRS PFM will be presented and compared to the theoretical expectations.

In 2015, we launched a program with the aim of preserving the scientific heritage of our laboratory, which entails conserving and showcasing historical documents and objects. Within this program, we offer internships that integrate history and science. One such internship focuses on utilizing modern optical design software to comprehend historical optical devices such as Charles Féry’s spectrophotometer from the 1910s. This approach illustrates how contemporary tools can illuminate the origins of scientific knowledge.

In this study, we have used the policy-gradient based reinforcement learning approach to generate initial design for microscope objective lenses. The lens parameters within the defined ranges can be determined by the model based on the given specifications. The results obtained from our analysis suggest that the reinforcement learning model can generate appropriate starting points which expedite the convergence of the optimisation process.

Traditionally, gradient-index (GRIN) optics have been made by varying the ratio of two distinct materials or exchanging two components within a base material. This has largely been dictated by manufacturing methods. However, due to recent advancements in additive manufacturing, GRIN optics can now be composed of a blend of multiple materials (i.e., more than two). It can be shown that these new, multi-material GRIN optics possess numerous advantages over traditional GRIN optics, especially in the realm of color correction. Such advantages arise due to multi-material GRIN’s ability to separately vary the GRIN power and the GRIN dispersion, a feat not possible with only two materials. Additionally, when the GRIN power is allowed to vary along the optical axis, the GRIN dispersion can also vary along the optical axis. This means that a single multi-material GRIN element can have regions of both positive and negative dispersion and regions that are extremely dispersive or nearly dispersionless. The ability to spatially tune the dispersion within a single optic is a powerful design tool which will be highlighted in this paper.

Minimizing distortion throughout zoom is often one of the most challenging aspects of a zoom lens design problem. In traditional aberration theory, distortion is analyzed through the fifth Seidel Sum. However, distortion can also be expressed as a sum of pupil coma and a second term we call the natural distortion, which is a quantity that is only dependent on the paraxial chief ray angles in object and image space. Examining distortion through the natural distortion and pupil coma provides new insights into the origins of distortion in optical design. Zoom lenses are a particularly interesting class of systems to analyze in this context because the distortion correction is typically more difficult than a prime lens. Using the natural distortion and the pupil coma, we explain why distortion is so difficult to correct in zoom lenses, as well as provide insight into trends in the behavior of distortion in commercially available zoom lenses.

Stress birefringence may lead to appreciable wavefront and polarization errors, especially in polarization sensitive systems. The effect is becoming increasingly important, as complex polarization-dependent and polymer-based optical systems become more prevalent, impacting imaging quality in systems such as Augmented and Virtual Reality. Advancements in multiphysics simulation, including the combination of Finite Element Analysis and optical simulation, enable optical designers to simulate and assess the effect of stress birefringence in the final performance of the optical system. We have developed a simulation method that combines 3D fitting of FEA non-uniform stress data with non-uniform gradient index ray tracing, calculating the polarization and wavefront error from the propagation of the wavefront through the system. We demonstrate the model with practical examples, in which we analyze the impact of stress birefringence on the polarization and image quality. The robustness of the technology is demonstrated with different types of stress data and optical systems.

Optical systems used in aerospace applications are often subject to random vibrations. These random motions cause optical elements to shift position, leading to image registration errors, and lower image resolution. Quantifying the impact of these vibrations is key to validating the design, and time is a new factor to consider. The sensor integration time draws a line between slow (drift) and fast (jitter) pointing errors. Distinct methods are introduced to assess the impact of drift and jitter. Besides, if traditional tolerancing tools can be used to model independent elements displacements, this approach is not applicable in the context of vibration analysis. First, the interdependency of each displacement is missed. Then, neither the actual surface deformations due to mechanical stress, nor the potential heating are considered. To successfully solve all these challenges, we propose a new Multiphysics drift and jitter analysis workflow to assess the performance impacts in optical systems using finite elements analysis (FEA) results, from tools like Ansys Mechanical. The behavior of the whole opto-mechanical assembly can then be considered, and the resulting effects of vibration imported back into Ansys Zemax OpticStudio using the STAR tools. Both structural data (surface deformations, rigid body motions) and thermal data (temperature gradient, automatically converted into a gradient index) are used to update the nominal design and compute the impact on the optical performance metrics. New tools have been developed to easily consider series of these datasets, to fully understand vibration impacts and their time dependence. The new insights gained from this new workflow will help taking enlightened decisions for the optical system design as well as its packaging to achieve better performances on system level, in challenging conditions.

We present the design and fabrication of a multicomponent optical system for LiDAR applications. The system comprises four stages: a commercial cylindrical lens, a custom freeform trilobe lens, a set of three custom reflective diffraction gratings, and a custom monolithic array of nine freeform mirrors. This optical set-up is coupled to an on-chip linear Optical Phase Array (OPA): the combination of linear beam steering provided by the OPA, and orthogonal linear steering achieved by the diffraction gratings results in a beam scan over nine directions in 3D. All the custom components have been designed and fabricated at VUB B-PHOT’s Photonics Innovation Center.

The correction of spatial and spectral resolution in imaging spectrometer systems is of great importance due to their significant impact on efficiency and quality. During the design process, the resolution and distortion are both essential for imaging spectrometer performance analysis and correction. In a spectrometer system, the prism or the grating usually break the rotational symmetry, causing problems in aberration correction. Therefore, freeforms can be introduced in such systems to improve the imaging performance with the additional degrees of freedom. Concerning the high-order surface deviation and the symmetry-free system structure, the mixed ray-tracing method is applied for a comprehensive aberration analysis. The results calculated with the method help for optical design with a clear visualization of surface-decomposed aberration contributions. In case of freeform application, the method is considered as a reliable tool for a better understanding of the imaging performance.

Adaptive optics (AO) ophthalmoscopy is a powerful technique for imaging retinas of living subjects at single-cell resolution. Traditional AO ophthalmoscopes use a fixed exit pupil diameter which is matched to the ocular pupil of a subject. A more efficient ophthalmoscope would allow for a variable exit pupil size to match the variable ocular pupil size of a subject. One method to achieve this is an optical zoom system. To make a zoom system appropriate for use in adaptive optics ophthalmoscopy it must be simultaneously well-corrected for both the field conjugate and the pupil conjugate such that the aberration correction can be successfully applied. The system must also be made of reflective optics to minimize chromatic aberration and spurious back reflections propagating through the system. Both these factors make for an extremely novel zoom system that requires new tools and methods to be developed in order to realize successful designs. We present here our work developing a new first-order starting point generator which creates valid first-order solutions that satisfy all the constraints of the system. We then show our techniques for modeling and optimizing the simultaneous conjugates of the system throughout the process of unobscuring the system. We find that to achieve the selected specifications that freeform optics must be introduced to the system to correct residual errors created during the unobscuring process.

Situational awareness requires systems with a wide field of view and a high angular resolution. Tackling both requirements is easier using freeform optics and a curved sensor and allows for compact systems. In this paper, we present an imaging system that fulfills these requirements in the visible spectrum, and the steps in the optimization process that lead to a viable system in terms of stray light.

HARMONI is the first light visible and near-IR integral field spectrograph for the Extremely Large Telescope. It covers a large spectral range from 470nm to 2450nm with resolving powers from 3300 to 18000 and spatial sampling from 60mas to 4mas. It can operate in two Adaptive Optics modes (including a High Contrast capability) - or with Non Adaptive Optics. The project is preparing for Final Design Reviews. In this paper, we present the optical design of the Pre-Optics for Final Design Reviews, the pre-optics take light entering the science cryostat (from the telescope or calibration system), reformatting and conditioning to be suitable for input for the rest of the instrument. This involves many functions, mainly relaying the light from the telescope focal plane to the integral field unit focal plane via a set of interchangeable scale changing optics. The pre-optics also provides components including a focal plane mask wheel, cold pupil masks, spectral order sorting filters, a fast shutter, and a pupil imaging capability to check telescope/instrument pupil alignment.

This paper discusses the challenges associated with designing a space-qualified Raman Spectrometer for lunar exploration, emphasizing the need for high sensitivity, compactness, lightweight, and robustness to withstand the harsh lunar environment. The Indian Space Research Organisation (ISRO) is developing a Raman instrument for future lunar missions aimed at identifying mineral constituents in lunar soil with resolution of 8 cm^-1 within the wavenumber range of 150 cm^-1 to 3800 cm^-1. The instrument's design features a monostatic configuration, employing a common optics system for laser focusing, sample positioning, and signal reception to mitigate misalignment errors. Key optimization considerations include mass, volume, and sensitivity, given the stringent constraints of space missions. The instrument utilizes a Volume Phase Holographic (VPH) transmission grating with a groove density of 1500 lines per millimeter (lp/mm) to meet performance requirements. This paper provides valuable insights into the challenges and design considerations inherent in developing Raman spectroscopy instruments for lunar exploration.

This paper introduces the tolerancing and design–for–manufacture in the catadioptric telescope for the remote sensing instrument (RSI) in the FORMOSAT–8 satellites program. The study utilized wavefront differential tolerance analysis to accelerate the tolerancing process efficiently. To address potential performance variations stemming from manufacture, assembly or alignment regulations, compensators were used to model these adjustments. The outcome delves into the strategic choices of specification and ion beam figuring (IBF) to trade–off manufacturability within the RSI system.

In this work we introduce a new category of diffractive lenses called multifocal binary Gabor zone plates (MGZP). These lenses are designed by integrating in a single plate multiple binary Gabor zone plates with distinct harmonic terms. We demonstrate how this binding allows the creation of a desired multifocal distribution that can be customized in the lens design to generate multiple focal points with adjustable focal distances of variable intensity. Numerical examples are presented of a bifocal and to a trifocal lenses with equi-energetic foci.

This study explores the design and refinement of a Mid-Wave Infrared (MWIR) continuous zoom lens system, which is coupled with a high-definition detector. Tailored to operate within a focal length range spanning 36-550 mm and offering a resolution of 1280 x 1024 pixels, MWIR imaging serves as a cornerstone in surveillance, defense, and remote sensing applications. Leveraging advanced optical design methodologies, this research aims to achieve heightened imaging resolution, mitigate aberrations, and counteract narcissus effects throughout the zooming spectrum. Furthermore, through meticulous manufacturing optimization, the production process is streamlined, ensuring cost-effectiveness and efficiency. The resultant MWIR zoom lens system showcases remarkable performance enhancements, promising superior image quality, and positioning itself as a versatile solution for diverse MWIR imaging endeavors.

Manufacturing a compact scanner head is necessary in the laser beam application development. As the first time proposed the scanner with deflection two laser sources beam just by one reflective element – polygon mirrors. This work will take a new look and comprehensive on polygon scanners. In terms of theoretical understanding, the 2D analysis of the scanner head needs to be addressed. This first step will give us the optical characteristics of the polygon scanner as well as give the future user a list of equations to design their own needed polygon scanner (desired scanning length, focusing length, size of polygon, number of facets. Although our main purpose in this study is to design a polygon scanner with two laser sources, we also examine the feasibility of using our polygon scanner for surface cleaning applications and optimize the scanner parameters to improve the efficiency of laser cleaning. We believe that we will design an innovative solution for ultrahigh-speed scanner.

With the aim of constantly reducing the prices and manufacturing times of space optical instruments, CNES has carried out research and development activities to evaluate new optical concepts for medium-resolution imaging applications. In reality, this study had two objectives. The first consisted of defining a disruptive optical architecture to significantly improve the compactness of telescopes. For this, we decided to target annular telescopes, which offer great compactness with a large numerical aperture, very interesting characteristics for small instruments. The second objective sought was to test a new manufacturing process, which will speed up production times. This is why the diamond turning point was chosen to create the prototype. We will therefore first present the optical design compromise between two interesting solutions for imaging applications. Detailed analyses were performed with optical software tools to prepare manufacturing files. In a second part, a description of the finalized prototype will be provided. It will focus on the opto-mechanical principle but also on the manufacturing quality obtained with diamond machining. Finally, we will detail all the characterizations on the prototype with and without sensor: optical performances evaluated in the laboratory as well as a set of images acquired on different realistic scenes. We will conclude and present perspectives for future versions.

We present highly miniaturized optical and electronic components for a two-channel fluorimeter with pin photodiodes with a very small detection limit (with an excitation of 100 μW and 590 nm, we detect one nW at 650 nm). One potential application lies in continuous monitoring of blood glucose levels. In a first step, novel dichroic beam splitter cubes made of fused silica with an edge length of 3 mm were developed. The diagonally dividing surface of the cubes was provided with a new dichroic layer system using the PARMS (Plasma Assisted Reactive Magnetron Sputtering) coating technology, which made it possible to achieve an angle of incidence of 45° (the current state of the art is more like 30°). The wavelength ranges are between 560 and 800 nm. In a second step, a special LED lighting unit with dimensions of 4 mm by 6 mm by 5 mm was developed. The angular distribution in the excitation beam that hits a dichroic beam splitter cube is limited to 3 degrees. In addition, very thin optically direction-selective filters have been developed to reduce stray light on the photodiodes. Here, glass substrates with a 100 μm thick Si-layer were used. This silicon layer was structured using inductively coupled plasma etching (ICP). Breakthroughs measuring 40 μm by 40 μm were created with inner walls made of black silicon. The transmission of these filters is 0.4 at angle of incidence at zero degrees and is less than 0.01 at angles of incidence greater than 13°.

Lenslet-based integral field units are notable for the large field of view and high throughput. But the structure in the image plane of these instruments is inherently highly complex due to the spatial and spectral packing of information, and often has large dynamic range between neighbouring pixels. This may make their optical design challenging in terms of the image quality and the technological complexty. We consider design options to implement such an instrument for a 40 cm - class telescope with a focus on the fast spectrograph camera design. It is demonstrated that with a relatively simple and compact optical system relying mainly on off-the-shelf components it is possible to reach the spectral resolving power up to R390 and cover at least 3.75′ angular field. It may be reached with a Schmidt camera or a custom 5-lens objective, using a curved sensor.

Microscopes are essential tools in research laboratories and hospitals to facilitate the examination of blood samples and other biological materials. As technological advancements continue to reshape the landscape of scientific research, there have been many enhancements in microscopy in terms of efficiency and automation of manual tasks. However, the process of slide scanning remains a labor-intensive task, particularly in developing and underdeveloped countries where access to expensive solutions may be limited. This research paper introduces an affordable 3D printed slide scanning stage equipped with an integratable camera to automate the image-capturing process at high magnification. The system, being powered by Arduino Mega, a versatile microprocessor, can support comprehensive 2D slide scanning with a significant range of motion (75 mm on the x-axis and 25 mm on the y-axis) and manage to drive multiple stepper motors in real-time (resulting in the precision of 3.9 microns per step). Both the area to be scanned and the magnification need to be provided in the code, and it will automatically calculate the remaining stuff to get the job done. There is an opto-interrupter sensor that provides feedback for every 166-micron movement of the stage, helping the system to accommodate for step missing or any external jerks during the movement. Furthermore, the user-friendly controls ensure a seamless experience for operators. These features collectively make the 3D printed slide scanning stage a valuable tool for various applications in research and medical settings, promising enhanced portability and precision.

The inherent dispersion of the glass utilized in lens construction necessitates applying various techniques to eliminate aberrations. Prior research has traditionally concentrated on single-spectrum applications, targeting either the visible or infrared region. In this study, we designed and conducted numerical simulations of an achromatic lens designed for the UV-visible spectrum, employing unconventional materials such as silicon nitride (Si₃N₄) and aluminum oxide (Al₂O₃). The Si₃N₄ serves as the equivalent of Flint glass, offering a high refractive index and a relatively lower Abbe number. Its transparent window extends from the deep ultraviolet (UV) range and covers the entire visible spectrum. Conversely, Al₂O₃ is well-suited for use as crown glass, given its lower refractive index than Si₃N₄ and a higher Abbe number, and Al₂O₃ remains transparent from the UV region till the mid-infrared region. Combining these two materials should yield an achromatic lens with eliminated chromatic aberrations. Therefore, lens design started with the achromat equations, and further optimizations were done using the ray tracing software Opticstudio Zemax. The Seidel diagram and focal shift graph offered empirical validation of our study's complete reduction of aberrations, and good focusing efficiency was achieved. The operational wavelengths in our study encompass a range from 360 nm to 633 nm, encompassing both the ultraviolet and visible spectra. Our work may apply to futuristic broadband imaging systems, collimators, and spectrometers.