Optical Design and Engineering X

LED-based illumination has become increasingly attractive for spectroscopy, imaging, and sensing applications thanks to their spectral diversity and compactness. However, efficiently combining the emission from multiple LEDs into a single, well-defined output remains a major optical design challenge. The overlap of multiple LED sources often leads to significant étendue mismatch, non-uniform illumination, and reduced optical efficiency. We present an overview of recent advances in the optical design of multi-LED systems, from state-of-the-art methodologies to a novel compact illumination architecture employing a single freeform mirror to collect and combine the LED emission beams. Particular attention is given to the role of the freeform mirror to spatially and angularly merge different LED channels, alongside an evaluation of the system’s optical efficiency, compactness, spectral homogeneity, and robustness. This design performance is supported by experimental validation within a proof-of-concept demonstration, paving the way towards its implementation in spectroscopic sensing applications.

The design of optics has seen very significant advances over the last seven decades or so, a lot of which has been due to the tremendous increase in the power of computing & software. In 1675, Isaac Newton said that “If I have seen further, it is by standing on the shoulders of giants”. The same is true of the optical designers of my generation in that we have benefitted so much from the work of the “giants” of previous generations. The presentation will therefore include brief synopses of the contributions of a few of these giants. Some selected examples will be given of the advances over the computer age in the means of designing optics and also the developments in specific optical devices. The presentation will be dedicated to the memory of John Greivenkamp, a great educator in optics, who was to have been its joint author.

Simulating human visual perception is essential for evaluating optical systems’ performance in virtual environments when the ultimate sensor is the human eye. Due to eye anatomical complexity—including the iris, lens, cornea and retina—accurate eye modeling would be essential for complete analysis of optical system performance from a human eye perspective. This work shows a validation study of the Reduced-Order Model (ROM) of the human eye in Ansys Speos, benchmarked with a biologically representative eye model originally designed in Ansys Zemax OpticStudio, including all the parts of the eye anatomy based on description in literature. A direct comparison of perceptual metrics such as contrast sensitivity and depth perception accuracy has been done in this study and shows near perfect correlation between the two models across varied lighting conditions and various scenes.

Harmony is a scientific mission operating two satellites flying in formation with Sentinel-1 to study ocean, ice, and land dynamics. Each satellite hosts a passive radar receiver and a multi-spectral thermal imager. Each imager has five cameras pointed at different view angles. A comprehensive Structural–Thermal–Optical Performance (STOP) analysis is essential to ensure that a spaceborne optical telescope meets its imaging quality and stability requirements under realistic on‑orbit conditions. It is usually performed multiple times during the development cycle because project knowledge matures, the optomechanical design undergoes revisions, and environmental conditions become more accurately defined. In the space environment, structural deformations and thermally induced distortions can slightly alter optical element alignment and surface figure, leading to measurable optical performance degradation. This paper presents the mission operating thermal effects on the Harmony TIR telescope’s optical performance and evaluates two approaches for integrating structural and thermal perturbations into the optical model.

The Double-Gauss (Planar) design is widely adopted when fast apertures such as f/2 or lower are needed for photographic and digital imaging applications. In this study, we examine the effects of imposing an image-side telecentricity constraint on this design type. We also trace the evolution of the Double-Gauss layout toward the Distagon configuration as larger apertures become desirable. Drawing on Glatzel’s research on microlithographic objectives, we explain this design transition leading to Distagon structures. We place special emphasis on field curvature, which emerges as the most challenging aberration to correct as apertures approach f/1 and below. Finally, we present a sequence of optical layouts for an unvignetted 50 mm focal length lens system operating in the visible waveband as the aperture expands from approximately f/3 to f/0.9. This demonstrates the growth in the system’s mechanical envelope that accompanies this expansion.

In this article, we propose an improved ray tracing method for metalens elements that accurately accounts for the polarization response of the meta-atoms so that the method can be used for the design and simulation of polarization sensitive metalenses. This improvement opens the metalens design space to more complex meta-atoms and optical functions. To demonstrate this workflow, we examine cases where metalenses are designed to provide different responses based on various polarization inputs and present a system where metalenses are assembled in a grid to create a polarization imaging system.

The modular principle in lens design represents a systematic approach to the synthesis of optical systems. Here, each module, which may be a lens, mirror, prism, or other element, as well as a group of elements, has its own specific function. That's the opposite of a brute-force approach, when one just adds more elements, aspherical or freeform surfaces, without assessing their feasibility for an exact optical system. For the case study, we use a monochromatic system, which must be turned into a polychromatic one, which is far away from the nominal wavelength. Color aberrations, induced by the nominal monochromatic design, makes conventional lens color correction challenging. We propose an approach for extreme color correction, utilizing a modular principle that provides a workflow, resulting in a non-conventional, well- corrected design.

Unobscured aperture reflective optical systems (such as TMAs, 4MAs,…) are widely used in space missions for their optical qualities, but the absence of systematic nomenclature complicates their classification and design, especially as Freeform optics diversify configurations. Traditionally, systems are identified by designer name or broad labels, which inadequately describe modern geometries. This work proposes a rigorous, additive nomenclature for multi-mirror anastigmatic systems, using compact notation to encode key features like mirror shapes and beam paths. This approach clarifies optical layouts, boosts understanding, and streamlines communication, aiding both classification and exploration.

Expert systems and deep learning methods have been used to automate starting-point lens designs and assist optimisation. While effective for well-defined tasks, these approaches depend on curated databases and human expertise, and typically require pre-defining optical element sequences. Such priors limit exploration of the design space and constrain what the model can learn, suppressing discovery of unconventional or optimal configurations, particularly for complex refractive systems. To enable exploration of potential designs, we employ reinforcement learning (RL) guided only by Snell’s law to autonomously design refractive lenses. The agent rediscovers known strategies while exploring various configurations, uncovering optimal arrangements of lenses and air gaps.

Obtaining initial designs in optical engineering is often challenging and mostly time-consuming. This work presents a systematic methodology for exploring the optical design landscape based on given specifications. It features a Requirements Editor for defining and managing important parameters, a Starting Design Generator that produces initial designs that meet the requirements and filtering tools to refine and help the user to pick his initial design. Additionally, an Alternative Design Generator is used that proposes alternative designs to further enhance the process of exploring. This workflow enables the users to transition from specifications to functional initial systems.

Adaptive optics ophthalmoscopes are optical systems used to image retinas in vivo at single-cell resolution. These systems have traditionally been designed with a fixed exit-pupil size to match a typical dilated pupil size, but an optical zoom system introduces the flexibility to adapt for a wider patient range. Reflective freeform zoom ophthalmoscope systems are novel designs whose performance highly depends on a well corrected starting point. A common design approach is to generate a large number of first order starting points which are candidates for further optimization. Currently, there is no metric to filter through these starting points, and individually optimizing them in optical design software is time consuming. We investigate an optimization method that minimizes the structural aberration coefficients across zoom positions. This eliminates the manual optimization of each individual starting point in an optical design software, making the design process much more efficient.

We experimentally characterize spiral lens performance at high field angles using PSF analysis and encircled energy metrics. Results demonstrate controlled field aberrations and extended depth of field properties, validating the spiral lens concept for compact imaging applications.

The design of intraocular lenses (IOLs) typically relies on standard eye models, which may not accurately represent eyes that have undergone refractive surgery such as LASEK. These surgeries modify corneal geometry and often increase optical aberrations, leading to less predictable outcomes with conventional IOLs. This study explores whether adding a freeform surface to an extended depth-of-focus (EDOF) IOL can improve visual performance in post-LASEK eyes. Using synthetic eye simulations, we compared conventional and freeform-enhanced EDOF IOLs. The results show that the freeform design reduces refractive errors and improves depth of focus consistency. This approach could enhance visual predictability for patients previously treated with corneal refractive surgery.

In this talk, the optical design of freeform volume holographic and computational holographic display systems is demonstrated. The use of freeform volume holographic element, combined with the joint optimization method of display system and recording systems, enables AR display systems with compact structure, reduced number of optical elements, and advanced functions. An end-to-end, system-level optical design framework of computational holographic display systems is proposed, accounting for the entire optical path from the illumination source to the retina, enabling full-color achromatic and high-performance displays with depth perception.

This study presents a comparative analysis of the geometries and and optical performance of three non-imaging concentrators for optical wireless communication receivers, including the compound parabolic concentrator (CPC), the dielectric totally internally reflecting concentrator (DTIRC), and a novel freeform concentrator. All designs use a 1.5 mm diameter detector, identical exit apertures, the same acceptance half-angle, and polymethyl methacrylate (PMMA) as the material. The CPC employs symmetric parabolic profiles (hollow or dielectricfilled), while the DTIRC utilizes a curved entrance surface and total internal reflection along its sidewalls. The proposed freeform concentrator is specifically optimized to achieve highly uniform irradiance distribution on the detector, overcoming the non-uniform illumination inherent in conventional CPC and DTIRC designs. Raytracing simulations demonstrate that the freeform concentrator provides more than 10% higher optical gain compared to the CPC and DTIRC, while maintaining irradiance uniformity exceeding 90%. At a 6◦ acceptance angle, its height is 5.97 times smaller than that of the CPC and 1.42 times smaller than that of the DTIRC. These results indicate that the freeform design offers a compelling combination of higher efficiency, better uniformity, and significantly more compact size for high-speed optical wireless receivers.

This study presents a coupled analysis workflow that integrates structural, thermal, and non‑sequential optical simulations for optical systems. We linked thermal‑structural analysis in Ansys Mechanical with optical analysis in Ansys Zemax OpticStudio, enabling non‑sequential optical simulations to incorporate refractive‑index changes and geometric deformation induced by optical absorption and mechanical stress under high‑power operation. Compared with sequential approaches, this coupled workflow offers greater flexibility and realism — for example, it facilitates precise source modeling, stray‑light analysis, and assessment of light absorption by mechanical components. As a demonstration, we analyzed optical elements subject to both mechanical distortion and thermal lensing. Our long‑term objective is to construct a digital twin that represents the coupled structural, thermal, and optical behavior of the system.

This work presents a five-step simulation workflow for designing and optimizing microLED-based indoor Visible Light Communication (VLC) systems using Ansys Lumerical FDTD, Ansys Zemax OpticStudio and Ansys optiSLang. The workflow begins with device-level modeling of a microLED transmitter to obtain far-field emission patterns, followed by system-level ray tracing in an empty interior modeled in Zemax. OptiSLang is then used to automate the optimization of microLED design to achieve a high coverage using a grid of beams mounted on the ceiling. Finally, a realistic 3D environment is modeled in Zemax, where the optical power is measured at a receiver of a user's device and the communication channel characteristics are evaluated. This integrated approach can greatly speed up the design and evaluation process of high-performing indoor LiFi systems and allows for accurate predictions of key metrics and enhanced multi-objective optimizations.

This paper presents a wide-field dual-band infrared remote sensing imaging system for forest fire monitoring and early warning. The system employs a common objective lens design to capture both mid-wave (3–5 μm) and long-wave (8–9.7 μm) infrared information, and utilizes two rows of detector arrays (totaling 2×23) to achieve stitched imaging over a 90° wide field of view. The objective lens adopts a fully symmetric spherical design, ensuring consistent imaging quality across all detector channels. Each detector is preceded by an aspheric refractive-meta surface hybrid lens, which corrects the residual monochromatic and chromatic aberrations from the objective. Through multi-channel joint design and optimization, the system achieves nearly diffraction-limited imaging performance with a large aperture of F/2, providing a ground resolution better than 100 m at an orbital altitude of 500 km.

We report the system design of an integrated ego velocity instrument to optically measure the 3D speed of uncrewed aerial vehicles (UAVs) in the absence of GNSS signals. Using a commercial frequency-modulated continuous-wave Doppler lidar, custom electronics and integration mechanics as well as additional sensors, the UAV-compatible Doppler instrument has been developed at ASENSE as part of a research project on autonomous vehicle navigation. We discuss the ego velocity algorithm and handling of outliers, and the performance of the instrument in terms of 3D ego velocity determination from a moving vehicle, as well as line-of-sight velocity accuracy and precision.

This study of optical design for drum projectors includes six projector lenses, which are divided into three flat-imaging lenses and three curved-imaging lenses. This article explores the different optical layout between flat imaging and curved imaging, and the impact of the different number of lenses, the presence or absence of curvature on the imaging surface, and its relationship to the imaging quality. Finally, except for some fields of view, the imaging quality of all designs is very good at a spatial frequency of 32lp/mm. In addition, adding elements to the lens might eliminate many aberrations. In the analysis of curved lenses, the obliquely incident light on the plane can be modified to a vertically incident structure, which also has the dual contribution to the elimination of field curvature. It is concluded that the overall imaging quality of curved lenses is better than that of flat lenses, which is valuable and worth further exploration.

In this study, we introduce a novel statistical framework for analyzing data obtained from human visual interpretation experiments. The proposed approach is formulated on the basis of the Fermi–Dirac distribution, a well-established statistical model in physics. In our implementation, an “optotype,” analogous to that employed in ophthalmological visual acuity assessments, is first defined as the fundamental stimulus parameter. The experimental outcomes—namely, the human visual interpretation rates—are regarded as a function of this optotype. By definition, the interpretation rate approaches 100% and 0% at the upper and lower limits of the optotype range, respectively. We model this relationship using the Fermi–Dirac distribution, substituting the energy variable with the optotype. Within this framework, the two intrinsic parameters of the Fermi–Dirac function, the chemical potential and temperature, serve as effective indices for quantitatively characterizing the properties of human visual interpretation behavior.

This work presents the design of variable curvature surfaces based on polynomials. The design is based on a variable curvature polynomial that uses a sixth-degree polynomial. This surface features a change in curvature from concave to convex in a small section, which acts as a barrier to slow down the movement of the friction pendulum in seismic isolation systems. In addition, a second similar surface was designed, but the points at which the curvature changes were selected to create two curvature changes, or two inflection points. This resulted in the surface changing from concave to convex and vice versa over a larger area than the first surface. These surfaces were manufactured using a stereolithography (SLA) 3D printer with a pixel size of 50 µm, which provides acceptable accuracy for surface manufacturing. Surface characterization is performed using optical deflectometry with off-axis null-screens.

This work presents the conceptual design of a Ritchey–Chrétien (RC) imaging telescope optimized for low-altitude Earth-observation small-satellite missions (approximately 300 km). Based on the orbital environment and mission requirements—ground sampling distance (GSD), swath width, and platform/packaging constraints—we establish optical performance objectives and explore the associated design parameter space. Although Korsch and three-mirror anastigmat (TMA) configurations were examined at the mission level, this paper focuses on the RC solution due to its implementation practicality and suitability for the target performance. The RC architecture employs hyperbolic primary and secondary mirrors to cancel spherical aberration and coma to first order, while its all-reflective nature minimizes chromatic effects and supports compact packaging for small-satellite payloads. To respect envelope and opto-mechanical constraints, we performed a layout trade study using two to three candidate configurations, varying primary–secondary separation, the field-flattener lens module, and folding-mirror placement. For each candidate, we quantitatively assess optical performance, including full-field MTF and distortion.

The correction of secondary axial colour is a major design driver in broadband optical systems requiring a careful balance between optical performance and the cost of special glasses. Traditional analysis methods often fall short of addressing the true nature of secondary colour aberrations in design. We present a unified framework that combines a data-driven approach to dispersion modelling with a simplified, single-term theory of induced secondary colour aberrations. This approach provides an accessible and practical description of secondary colour effects, enabling deeper understanding and improved material selection for system optimization.

Bio-inspired, macroscopic foam- and sponge-like geometries are investigated for stray light reduction applications, without necessitating alterations to the surface coating. In a proof-of-concept study, exemplary structures resulted in reductions of reflected peak intensities by factors of less than 0.39 and average intensities by factors of less than 0.65, when compared to an unstructured reference. Engineering designers can balance structure and surface durability, residual stray light propagation directions, weight, stiffness, heat transfer and thermal expansion. Additive techniques such as powder bed fusion or fused deposition modelling enable sustainable fabrication. The approach offers robust, cost-effective absorbers made from durable materials like black anodised aluminium or ABS polymers, among others.

Purpose: Current refractive extended depth of focus (EDOF) intraocular lenses (IOLs) are sensitive to the level of corneal spherical aberration (SA), and some exhibit pupil-dependent performances. As laser-assisted in situ keratomileusis (LASIK) can significantly alter corneal SA, the purpose of this study was to assess the impact of spherical aberration changes after refractive surgery on the pupillary behavior of EDOF IOLs. Method: Three commercial EDOF IOLs (AcrySof IQ Vivity, Bausch & Lomb LuxSmart, SIFI MiniWell) were simulated using literature-based data. The performances of these lenses, in terms of through-focus visual acuity, range of field, CDVA and DCIVA, were evaluated in a Liou & Brennan eye model. This model was adapted to take into account different pupil sizes and spherical aberration values, representing respectively normal eyes and eyes that had undergone hyperopic or myopic (average/strong) refractive surgery. Results: Corneal spherical aberration (SA) induced by LASIK surgery significantly altered the pupillary behavior of all EDOF lenses. Hyperopic LASIK shifts the location of the best visual acuity towards positive defocus values, increases the range of field, may decrease CDVA while improving DCIVA. Conversely, myopic LASIK induced SA shifts the location of the best visual acuity toward negative defocus values, decreases the range of field, and may improve CDVA while degrading DCIVA. Conclusion: Post-refractive surgery corneal spherical aberration significantly affects the performance of EDOF IOLs with pupil diameter. A thorough understanding of each IOL’s pupil-dependent behavior, such as the ones presented in this study, is essential for optimal lens selection and power calculation before refractive surgery.

We present a proof-of-concept investigation that combines simulation-based design-of-experiments with Gaussian process regression to accurately predict freeform surface figure deformations (“sfd”, polynomial coefficients) and rigid body motions (“rbm”, coordinates) from a node-displacement point cloud as input. When accounting for inhomogeneous thermoelastic phenomena within optical design processes, we couple optical and thermoelastic simulations. Especially when targeting automatized opto-thermoelastic optimization of distinct perturbation compensators, it is critical that fits to perturbed point-clouds accurately distinguish between rbm and sfd, respectively. Here, we commonly face challenges by ambiguities. We generate multiple training datasets and surrogate models. A first dataset with variances for rbm and sfd is used to train individual regression models for each rbm component, respectively. A second dataset with variances only applied for sfd is used to train a single regression model to predict freeform surface polynomial coefficients. Tests with independent datasets hint the hierarchical surrogate model can achieve accuracies exceeding 99.9999%.

This study presents the optical design and performance evaluation of a Ritchey–Chrétien telescope with a two-element corrector, developed for high-resolution Earth-observation imaging on a 3U CubeSat. The system utilizes a reflective configuration with a square 80 mm × 80 mm primary mirror (M1), and an effective focal length of 900 mm. The corrector compensates for optical aberrations, enabling near–diffraction-limited performance across the field of view. At an operational altitude of 500 km, the telescope achieves a ground sampling distance (GSD) below 5 m and a swath width of 7.4 km × 7.4 km, corresponding to a full field of view (FOV) of 0.84° × 0.84°. The design maintains a modulation transfer function (MTF) exceeding 0.20 at the Nyquist frequency, corresponding to a detector pixel size of 6.5 µm. A comprehensive tolerance analysis has been conducted, addressing manufacturability, alignment sensitivity, and structural stability.

One of the main challenges of optimizing optical designs lies in handling discrete elements, such as selecting lens materials, test plate substitution or incorporating off-the-shelf components. Most commercial optical design packages allow for such optimizations, but results are not optimal, and the process is time consuming. The quantum computing department of the Netherlands Organization for Applied Scientific research (TNO) has implemented an AI-driving optimization method called QAFM (Quantum-Assisted Factorization Machine). This algorithm has demonstrated promising results in various fields particularly for problems involving discrete optimization. In this paper the possibilities of adapting this method for optical design of systems that requires element substitution are explored. The AI-driving discrete optimization project had two main goals: On one hand, it applied the QAFM model to the field of optical design, generating a set of optical designs compliant with the optical designer requirements. Second, developed a reusable, user-friendly and versatile implementation was developed which allows for knowledge transfer and paves the way for future applications.

Computational imaging and display principles are key enabling technologies with the potential to transform a wide range of future applications. New types of cameras could see through deep tissue, fog, or smoke. Fast and precise 3D scanners could improve medical diagnosis and therapy, and become essential for measuring dynamic scenes in robotic surgery, autonomous navigation, or additive manufacturing. Advances in 3D display and eye-tracking technologies could spark the next wave in AR/VR. Amidst these possibilities, understanding the fundamental physical and information-theoretical limits in computational imaging proves to be a powerful tool: Limits often appear as uncertainty relations, guiding us to optimize critical system parameters (e.g., speed or accuracy) by trading off less essential information for a given task. This talk will highlight the virtue of limits in computational imaging by discussing our recent research activities in industrial inspection, medical imaging, and AR/VR. Topics include new methods for high-accuracy eye tracking as well as high-speed, single-shot 3D metrology on challenging shiny surfaces for the inspection of metallic objects and surgical robot navigation. Moreover, I will introduce a set of techniques that use so-called “synthetic waves” for computational holographic imaging through scattering media -such as biological tissue- which also allow the capture of “light-in-flight” information without the need for pulsed lasers or fast detectors.

We present a co design framework built on the differentiable ray tracing software which provides accurate, differentiable simulations of complex optical systemswithin an optimization pipeline. We extend this framework to incorporate image reconstruction based on Wiener filters, allowing simultaneous optimization of the optical design and the associated signal processing algorithm. We present an example where this framework is used to jointly optimize a Petzval aspheric system used with a single Wiener deconvolution, with the goal of extending the depth of field while retaining satisfactory performance across the whole field.

Optical systems for aerospace applications, such as space flight instruments and satellites, are under significant thermal loads due to solar radiation which highly impacts their overall performance. Therefore, during the design process, it is important to evaluate the performance of the system under mission-specific environmental conditions. Accurate design requires a multiphysics simulation approach to estimate the thermally induced optical performance degradation under operational conditions throughout the full mission. Structural Thermal Optical Performance (STOP) analysis offers a solution to get an early insight into the design and steer the optimization and calibration process accordingly. In this study, we are going to present an automated multiphysics approach to simulate STOP analysis considering the mission, integrating thermal, structural, and optical effects to ensure accurate system performance predictions using Ansys solutions. This workflow supports streamlined collaboration among different physics-specialized teams within an integrated multiphysics framework, based on a synthetic operational environment.

In this article, we present a novel workflow whereby a metalens is integrated into a GC PIC setup and investigate the resulting system efficiency and tolerance of waveguide-fiber coupling to lateral fiber shifts. Our multi-scale workflow provides an efficient integration of the metalens element into the optical system with a combination of ray tracing and wave -optics propagation methods. The coupling efficiency and losses of this design are computed in both directions and directly compared to those of the microlens-integrated GC design, and tolerance of the system to shifts in fiber position is assessed.

Wide field-of-view imaging systems frequently suffer from distortion, resulting in a reduced design performance and a more difficult sensor calibration, particularly within thermal imaging systems. This work investigates the impact of distortion functions across rectilinear, equiangular, and equisolid projection schemes, while tackling the optimization of a compact three-lens thermal (8–14 μm) imaging design featuring a full field-of-view of 140°. Both the equiangular and equisoliod designs outperformed the traditional rectilinear design, showing a uniform relative illumination exceeding 75%, and a minimal distortion (<2%). The equisolid design demonstrates a superior image quality, achieving a (geometrical) diffraction-limited performance across the full FOV. As a result, our presented design approach highlights the importance of optimized projection functions in wide field-of-view imaging systems, illustrating how alternative distortion models can offer a viable path towards systems with enhanced image quality, especially when considering detectors with smaller pixel sizes.

Ultrashort laser pulses are widespread in scientific and industrial areas and have a large number of application fields : laser materials processing, surgery, nonlinear microscopy are few examples. However, for these applications where the optical path can be very complex, the spatio-temporal profiles can be strongly affected by the optics. This highly impacts on the effective pulse duration, the group velocity, and, as a consequence, on the efficiency of the targeted nonlinear mechanisms. Simulating the spatio-temporal profiles for any arbitrary optical system is at present a challenge. Here, we demonstrate that using a combination of ray tracing software and a scalar wave description of the laser pulse, one can model the spatio-temporal shape of femtosecond laser pulses after a pulse shaping and complex optical setup. Our numerical results have been assessed using analytical results and compared to literature.

The Mezzocielo project is an innovative telescope is being designed to observe nearly the entire night sky simultaneously. It features a hollow sphere, made of spherical N-BK7 glass meniscus shell, filled with a transparent liquid that together acts as a light collector, focusing the incoming light to a multi-channel correcting system. The telescope covers an ultra-wide field of view of about 10,000 square degrees, managed by a multi-channel corrector architecture with approximately 900 channels. Each channel is equipped with a dedicated optical train and a CMOS detector. In this study, we present the optical design and iterative development of a corrector for an 80 cm on-sky demonstrator. The design process is driven by the need to balance image quality, light collection efficiency, detector sampling, manufacturability, and channel packing constraints. The current corrector design achieves a field of view of approximately 5° in diagonal across a spectral range of 500--800 nm with a 360 mm equivalent aperture, leading to approximately 45% of the 800 mm diameter sphere. The optical assembly consists of field lenses, spherochromatism-correcting elements, and an objective group. Lens diameters, curvatures, and aspheric content are limited to ensure manufacturability and enable replication across adjacent channels.

The Wide-field Spectroscopic Telescope (WST) is a proposed 12-meter segmented facility optimized for seeing-limited observations in the visible and designed to operate both a high-multiplex multi-object spectrograph and a panoramic integral field spectrograph (IFS). The WST IFS concept builds on instruments such as MUSE at the VLT, using field splitters and image slicers to reformat a large field into pseudo-slits feeding spectrographs with two optimized spectral channels. This paper presents the spectrograph architecture developed for the WST IFS, aiming to achieve high throughput and image quality over a wide wavelength range in a cost-effective manner. We investigate the use of curved detectors as a means to simplify the spectrograph layout, reduce aberrations, and potentially improve efficiency. This study establishes a promising baseline for the IFS spectrographs and assesses the benefits of incorporating curved sensors that can guide the development of future large-scale integral field spectrographs.

We present an optical analysis of BISOU (Balloon Interferometer for Spectral Observations of the primordial Universe), an astronomical balloon-borne pathfinder instrument developed as part of a preparatory study for a future space mission aimed at measuring spectral distortions of the cosmic microwave background (CMB). The BISOU optical system is based on a differential polarizing Fourier Transform Spectrometer (FTS) that receives inputs from both a sky-facing telescope and an internal calibration source. The FTS focal planes are equipped with bolometric detectors coupled to multimode feed horns, with distinct focal planes dedicated to the low- and high-frequency bands covering the 90 - 1500 GHz range. The optical analysis first relies on ray-tracing simulations to establish the overall configuration of the system, before proceeding to more advanced Gaussian beam and physical optics analyses.

A compact four-band SWIR optical payload compatible with nanosatellite Earth remote sensing missions is being developed. The optical system uses Maksutov scheme with the aim of achieving 20m GSD at a 600 km orbit. The designed instrument includes mechanically controlled 4 SWIR bands with a width greater than 60 nm, and InGaAs detector with range of 1.2¬ – 2.2 µm with resolution 650x512 of 15 µm pixels.

Diffractive sensors consist of a diffractive mask located in the common focal plane of a 4-f optical system. A camera is placed behind this system, detecting multiple versions of the entrance pupil, each with its own modified spatial frequencies. From these, the wavefront slopes can be extracted. This type of sensor is compact, robust, and offers high resolution. Its main disadvantage is the need for high light intensity, which limits its use in adaptive optics, although this is not a problem in optical communication applications. This presentation introduces the fundamentals of diffractive sensors and shows some examples. It also demonstrates that wavefront retrieval is simple and can be performed almost in real time. Although it is a developing technology, it shows very promising prospects compared to other more established sensors.

We demonstrate a computational tool and design methodology for generating lens designs built completely from commercially available Off-the-Shelf (OTS) components with integrated assembly tolerances (e.g., 3D-printing vs. precision mounts). This tool enables optical designers to quickly design, evaluate and test complex optical designs for applications such as spectroscopy, microscopy, scan lenses and machine vision. By relying on Fermat’s principle to systematically generate constrained, stock-based lens systems of both finite and infinite conjugate configurations from scratch, we significantly accelerate the design and prototyping process, truly unlocking OTS capabilities for industrial innovation.

Project-driven and smart teaching platform-empowered optical system design course teaching reform is explored. The reform introduces multiple cutting-edge real-world enterprise projects and full-process scenarios into the optical system design course, completing closed-loop training of students from scheme conceptualization to finished product validation. An AI-based smart teaching platform integrating MOOCs, knowledge graphs, Large Language Model (LLM), and 7×24-hour intelligent teaching assistants has been developed. It supports students in independent theoretical learning and basic software operation, while delivering data-driven recommendations for a personalized learning path.

We present a rigorous methodology for real-time tolerance and sensitivity analysis applicable to multi-element optical designs. The central novelty is the derivation of exact, closed-form analytical expressions for all relevant optical performance derivatives with respect to manufacturing and alignment parameters. Derived from Fermat’s principle, this approach is universally valid and eliminates computationally expensive iterative ray tracing. These analytical expressions provide immediate sensitivity data for metrics such as RMS spot size and RMS wavefront error (WFE), enabling a true Design-for-Assembly (DFA) assessment. We demonstrate an orders-of-magnitude reduction in computation time compared to traditional Monte Carlo (MC) benchmarks while maintaining accuracy for systems based on Off-the-Shelf (OTS) components.

The lens groups of a zoom system can be designed independently using a variety of techniques, including artificial intelligence (AI). While reoptimization is still required after the lens groups are combined to form the complete zoom lens in traditional optical design software, designing the lens groups individually can speed up the design process and reveal underlying principles of zoom lens design. The groups can be designed to have predetermined aberration contributions, as well as other favorable properties like small ray angles and short length. The group design problem is explored with aberration theory and empirical evidence from patent literature. Tools and methods for designing lens groups, including conventional optimization, Monte-Carlo searches, and a new AI-based method, are developed and analyzed. Furthermore, we highlight the necessity of a strong understanding of aberration theory to successfully implement an AI lens design program, despite the ever-increasing power of AI.

Light-sheet fluorescence microscopy has emerged as the method of choice for imaging thick 3D cell cultures, cancer spheroids, and small organisms, offering high-quality visualization while minimizing phototoxicity. However, commercially available light-sheet microscopes are mostly bulky and expensive. In this work, we designed and build a compact light sheet illumination add-on module for upright water-dipping optical microscopes that can turn easily them into light-sheet microscopes. An optical design using off-the-shelf available reflective and refractive optical components was tackled, followed by a tolerance analysis and optomechanical implementation. A high-quality light-sheet was obtained and confirmed in the lab, successfully demonstrating the 3D imaging of cancer spheroids.

At sub 5 nm wavelengths, XUV projection systems offer one potential path toward the next generation of lithography systems. Alternative paths such as hyper NA EUV suffer from a smaller depth of focus, raising challenges for wafer alignment. XUV optics remedy this through a combination of a reduction in wavelength and a return to lower numerical aperture, allowing for higher depth of focus at an improved resolution. This work surveys the reflective design space for XUV projection optics by adapting current EUV finite conjugate relays to shorter wavelengths. Both classical aspheric and freeform designs are examined across a range of field sizes, magnifications, numerical apertures, and mirror counts. A custom CODE V macro is used to automatically generate clearance constraints for arbitrary complex folding geometries, saving time during the design process. These considerations establish a coherent structure for further development of XUV projection optics.

PRIMAger is an infrared imager onboard the PRobe far-Infrared Mission for Astrophysics (PRIMA), an infrared observatory for the next decade, currently in Phase A, with a 1.8 m telescope actively cooled to 4.5 K. PRIMAger will provide observers with a coverage of mid-infrared to far-infrared wavelengths from 24 to 264 μm and will offer two imaging modes: the hyperspectral mode from 24 to 84 μm wavelength range with a spectral resolution R ≥ 8, and the polarimetric mode in four broadbands from 80 to 264 μm. The current paper presents the baseline optical design of PRIMAger. This design, based on off-axis freeform aluminum mirrors, permits to meet the critical requirements in terms of field of view, focal ratio, image quality, telecentricty and pupil stability. A detailed description of the principle and the analysis of the optical performances and tolerances are studied. Other important aspects such as mirror manufacturing feasibility, straylight minimization and self-polarization behavior will be discussed. The alignment strategy and the verification plan will also be presented.

We investigate a mechanically tunable Fresnel lens whose focal length and resulting wavefront shape can be adjusted by controlled deformation of the substrate. A coupled workflow links finite element simulation with optical modeling to map applied radial displacement to the resulting optical performance. Deformed surface profiles generated in Ansys Mechanical are evaluated in Ansys Zemax to quantify changes in focal length, wavefront error, and spot quality. To validate the simulations, a laboratory setup with a manually adjustable holder is implemented. A Fresnel lens made from polydimethylsiloxane (PDMS) is mounted in a simple frame that allows defined radial displacement, while a collimated beam and a camera are used to record the focal plane. The results confirm that mechanical deformation is an effective and predictable strategy for tuning Fresnel lenses.

To enable accurate observations of low surface brightness (LSB) astronomical structures, the K-DRIFT (KASI Deep Rolling Imaging Fast Telescope) G1 system has been developed at the Korea Astronomy and Space Science Institute (KASI). The telescope employs a Linear-Astigmatism-Free Three-Mirror System (LAF-TMS) optimized for wide-field imaging with minimal aberrations and high optical throughput. Since LSB observations are highly sensitive to unwanted illumination, a detailed stray light analysis is essential to ensure sufficient system contrast and uniform background levels. In this work, we performed a model-based stray light analysis using scattering and coating models. The scattered light was evaluated using the Bidirectional Scattering Distribution Function (BSDF) model to represent microscale surface structure and coating effects, while ghost images were modeled based on optical coating properties to account for multiple internal reflections. To quantitatively assess stray light performance, the Point Source Transmittance (PST) was computed to trace stray light propagation from both on-axis and off-axis sources. The PST-based analysis identified dominant stray light paths and guided the design optimization of baffles and vanes, effectively reducing unwanted light and improving system contrast. The results demonstrate that combining scattering and coating models with PST-based evaluation provides a practical and accurate approach to predicting and mitigating stray light in asymmetric wide-field telescopes such as the K-DRIFT G1. Future work will extend the analysis by incorporating experimentally measured BSDF and coating properties, thereby enabling more realistic and accurate predictions of stray light performance within the K-DRIFT G1 telescope.

In optical systems utilizing multiple diffractive surfaces, the number of potential non-design order combinations grows combinatorically. To meet stringent 'as-built' MTF performance, a predictive understanding of how the PSF contributions from the stray order combinations coherently interfere with the design order PSF and an idea on the potential contrast degradation is essential early-on in the design phase. The challenge is exacerbated in zoom objectives, particularly when a diffractive surface is used in a moving group. This paper presents a continuous zoom objective as a design example with multiple diffractive surfaces, and an approach utilizing the sum over orders (SOO) method to analyze the cumulative impact of all possible stray order combinations. The methodology involves sorting combinations by their normalized irradiance to identify the most significant contributors. An approach to determine appropriate weighting for these combinations based on their energy distribution and on the spectral range is also discussed in this paper.

In optical designs controlling straylight is essential to avoid unwanted artefact. Once an appropriate coating is designed regarding the optical elements, annoying artefacts still exists and are generated by mechanical elements, e.g. diaphragm, nuts, spacers. Consequently, we conducted spectral total reflectance measurements of sulfuric acid anodized titanium elements over [450nm;1000nm] wavelengths range, as well as specular and diffuse reflectance measurements over [580nm;615nm], [700nm;740nm] and [840nm;920nm] wavelengths ranges. Bath voltages ranging from 8V to 100V were considered. Results indicate that reflectance spectra of mechanical components can be controlled to minimize reflections over considered wavelength ranges. They also suggest that depending on the bath voltage, portion of specular reflectance over total reflectance varies from 3% to 24%.