This PDF file contains the front matter associated with SPIE Proceedings Volume 12765, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

The traditional method of monitoring cameras is employed in robot vision, surveillance cameras, and so on. However, it cannot track as fast as expected due to the large inertia of the camera and mechanical pan-tilt. It also decreases the optical resolution because of the digital zoom on the interest area. Therefore, we proposed high-speed zooming and tracking optics that consists of an optical zooming unit and an active tracking unit. The two units are designed with coaxial optical paths by a beam splitter. The zooming unit is built with three liquid lenses, one glass lens, and a high-speed camera. It can continuously change the magnification from 1x to 2x. By controlling the optical powers of three liquid lenses, the focal length of the zooming unit can be changed from 40 to 80 mm within milliseconds. The tracking unit composed of a high-speed mirror-based gaze controller, a high-speed camera, and pupil shift optics, can track the object and keep it in the center of both views. In addition, the zooming unit provides a compensation algorithm for the zooming unit to achieve adaptive zoom accurately. The experiment shows that the zooming unit performs adaptive optical zoom, and the tracking unit recognizes the object by adaptive tracking algorithm within 6 milliseconds.

We present a varifocal near-eye-display with large eyebox and vision correction capability. The proposed scheme uses a dihedral corner reflector array (DCRA) and a varifocal lens. The DCRA forms a real image of the varifocal lens onto the eye pupil plane, creating larger eyebox than the conventional system at the same varifocal lens aperture size. The vision correcting optics can be placed at the side of the eye, clearing the space between the eye and the optical combiner. Detailed system configuration and the experimental results will be introduced in the presentation.

For an advanced three-dimensional (3D) light field display, the 3D image information with correct spatial occlusion relation should be provided in a large viewing angle range. However, the optical distortion and the structural error are two key factors of the deterioration in image quality, which cause the serious deformation of 3D images, especially in large viewing angle. Here, the light path of spatial voxel is analyzed. The mathematical relationship between optical system parameters and spatial voxel positions is achieved. The aberration theory is used to analyze the optical distortion of single lenses. Due to the influence of optical distortion, the angle of the emitted light deviates from the ideal direction, which leads to the deviation of spatial voxel positions. The compound lens with aperture-stop is designed to suppress the optical distortion. The optical performance of optimized compound lens is evaluated. In order to further suppress the residual optical distortion and the structural error, a pre-correction method with the detection of optical path error is proposed. The correspondence between the pixel of display source and the spatial voxel is obtained. Based on the designed compound lens and pre-correction encoded image, a 3D light field display system is constructed. Experimental results demonstrates that the proposed method suppresses the optical distortion and the structural error. An undeformed 3D image with the viewing angle above 100 degrees can be achieved, which can find potential applications in biomedical imaging and visualization to enhance medical analysis and diagnosis.

We have developed a novel point-polygon hybrid method (PPHM) for calculating computer-generated holograms (CGHs), which takes advantage of both point-based and polygon-based methods. While point-based methods are good at presenting object details, polygon-based methods are good at efficiently rendering high-density surfaces with accurate occlusion. The PPHM algorithm combines the strengths of both methods and eliminates their weaknesses to achieve higher computational efficiency. It utilizes a low-polygon approximation of the original 3D polygonal meshes and leverages the computational advantages of the wavefront recording plane and look-up table methods to generate high-resolution holograms with smooth focal cues quickly. The proposed PPHM algorithm is validated to present continuous depth cues and accurate occlusion with fewer triangles, implying high computational efficiency without quality loss.

Nonlinear rays are described by the eikonal function, which bridges the gap between wave and geometrical optics. These nonlinear rays follow a path that is always normal to the phase front as it propagates in space. In this paper, we explore how to augment the classical geometrical ray-optics approach to calculate the forces acting on the sphere in an optical trap developed by Ashkin, such that non-linear rays can replace linear rays in the calculation. The greatest advantage of such an approach would be be the capacity to model the orbital angular momentum imparted on the sphere using a Laguerre-Gaussian spatial mode laser. The non-linear rays associated with any convering wavefield can be traced towards their intersection point on the surface of the sphere and for each one of these ’rays’, the scattering force, gradient force, and torque can be derived using the Equations defined by Ashkin. Integration of these forces reveals the total three-dimensional force acting on the sphere as well as total rotational forces which can be decomposed into a ’vertical torque’ and ’horizontal torque.’ As well as investigating the single beam dielectric trap in the model of Ashkin, we additionally investigate the dual beam trap for all cases, which has the benefit of enhanced trapping forces.

Micro light-emitting diode (Micro-LED) has the advantages of high brightness, low power consumption, and long life. It has great potential and broad application prospects. Using micro-LED as the light source and image source of the projection system can greatly reduce the size and power consumption of the system. However, the electrical module and the optical module of the micro-LED pico-projection system cannot be separated. This paper uses image fiber to effectively separate the electrical module and optical module in the optical engine, and designs a micro-LED pico-projection optical engine based on an image fiber. This optical engine is composed of a projection lens group, an image fiber and a micro-LED. The projection lens group is composed of 5 spherical lenses, with the total length of 6.752mm and the focal length of 2.8mm. The modulation transfer function (MTF) is higher than 0.8@32lp/mm, and the distortion is below 2%. The image fiber adopts a multi-core fiber with a diameter of 2mm and a resolution of 32lp/mm. Finally, the overall simulation model of the optical engine is built to prove its feasibility.

In recent years, Mini-LED has been widely used in direct-lit backlight for Liquid Crystal Display (LCD) widely due to its advantages of miniaturization and low power consumption. Typical Mini-LED direct-lit backlights mainly rely on the diffuser plate to convert point-like light sources into uniform surface light sources. However, the diffuser plate cannot achieve high uniformity at a very low optical distance (OD). In this paper, we introduced the pyramidal microstructure and the semi-cylindrical microstructure to both sides of the optical film, respectively. The mechanism of influence of the pyramidal microstructure and the semi-cylindrical microstructure on light was analyzed. We clarified the relationship between the parameters of the microstructure (the pyramid angle, the pyramid dimension) and the illuminance uniformity by simulation. Moreover, two layers of microstructure optical films are discussed and simulated. Through the simulation, the optical effects are evaluated and analyzed from the point of illuminance uniformity. Simulation results maintain that when the OD is 5mm, the illuminance uniformity reaches 93.07%. Compared with the diffuser plate with a thickness of 1.5mm, the thickness is reduced by 0.9mm, and the illuminance uniformity is increased by 11.77%. This work fully demonstrates the advantages of the microstructure optical film to improve the illuminance uniformity.

Designing a metalens of millimeter scale or larger is challenging. We demonstrate how to combine a ray-based automatic design tool with a wave-based inverse design tool to design a mm-size ultra-wide angle metalens imaging system. The ray-based approach parametrizes the distribution of meta-atom design parameters over the surface with a polynomial, and treat the metalens similarly to a grating. The ray-based design tool considers both the transmission and the phase of the meta-atoms as functions of the incident angle. The ray-based approach is fast and robust. It can complete the optimization of a mm-size metalens in a few minutes. This design can then serve as a starting point for a wave-based inverse design tool. The wave-based inverse design tool is applied to further optimize the metalens with arbitrary distribution of meta-atom design parameters. The additional design freedom offered by the arbitrary distribution further increases the light collection efficiency and image resolution. Finally, the design performance is validated with a finite difference time domain (FDTD) algorithm. All analysis results agree well, show that the final ultra-wide angle metalens design is close to diffraction limited. These results demonstrate the effectiveness of our proposed workflow by taking advantage of both the ray-based and the wave-based design tools.

Off-axis reflective zoom imaging optical system has a wide range of applications in the field of photoelectric detection because of its advantages of chromatic aberration-free, broad-spectrum imaging. The existing off-axis reflective zoom imaging optical system has a fixed pupil diameter, and as the focal length becomes larger, the relative aperture becomes smaller, resulting in a lower signal-to-noise ratio and weaker detection capability. Additionally, aberration correction is vitally important in the off-axis reflective zoom system with large relative aperture. An attempt to improve the performance of an off-axis reflective zoom imaging system with large relative aperture using freeform surface is reported. The F number is 4, and the zoom ratio is 3. The optical design with freeform surfaces shows marked improvements compared with the design with higher order aspheric surfaces.

Illuminator is one of the important components of extreme ultraviolet lithography system. Industrial extreme ultraviolet lithography illuminator uses two compound eyes and relay system, which can realize variety of illumination modes. But the manufacture and assembly of compound eyes are difficult. Therefore, we would like to design illuminators, which use such as Offner-relay system, quad elliptical mirrors, or other mirror systems. These systems do not have more complex surfaces, easier to assembly. Analyze advantages and disadvantages of these systems, and then discuss the possibility of using these systems in industrial extreme ultraviolet lithography.

This paper presents the design of a fast aperture, high resolution, wide-angle, optically passive athermalized long-wave infrared (LWIR) lens suitable for driver vision enhancer systems. The growing demand in high resolution thermal imaging has led to the need for advanced lens designs that can deliver exceptional performance in this electromagnetic spectrum. The proposed lens design focuses on achieving a fast aperture, which is crucial for capturing object details in modern bolometer arrays with smaller pixel pitch. Additionally, the design provides a wide-angle field of view to enable comprehensive scene coverage. The use of optical passive athermalization technique also ensures that the lens maintain its performance across a wide range of operating temperatures, thereby eliminating the need for any active temperature compensation mechanisms. In order to achieve a large image diameter, the lens design incorporates aspheric and diffractive surfaces, as well as a combination between conventional and chalcogenide materials. These elements help to minimize optical aberrations and increase image sharpness. With the use of computer-aided design software and its corresponding optical simulation tools, the design was refined to meet the desired specifications, including resolution, field of view and athermalization requirements. The resulting lens design managed to achieve a horizontal field of view of 76 degrees with a fast aperture of F1.0 for an uncooled 12-micron SXGA detector. This design ensures consistent and nearly diffraction-limited performance in diverse operating conditions, making it suitable for driver vision enhancer systems, as well as the general automotive applications.

We previously optimized the freeform surfaces using extended polynomials in stereographic projection coordinates based on an automated workflow linking the optimization engine, 3D modeling software and ray tracing software [Optics Express 29(9), 13469–13485 (2021)]. However, this method is time consuming as it needs thousands of irradiance evaluations. Here, we speed up the optimization of spherical-freeform lenses for uniform illumination based on differentiable ray tracing. The freeform surface is still parameterized with the ‘uv’ extended polynomials under stereographic projection coordinates, which is suitable for generating simple illumination patterns. We implement differentiable ray tracing based on computation graph in MindSpore framework, which is efficient and effective by calculating derivatives of the surface parameters during a single backpropagation. We provide two design examples for generating uniform irradiance distributions with a point-like source and an extended light source, respectively.

Freeform optics offers advantages over sphere and asphere in Aberration correction, volume saving, and imaging performance improving. Freeforms are essential components in many optical systems such as augmented reality head mounted display, automotive augmented reality head up display, LiDAR system, smartphone camera, high performance lithography system, and etc. This paper will show and discuss several designs or applications of freeform optics. The applications of freeforms in more systems would be the focus in the next work.

The edge-emitting laser diodes (EELs) are widely used due to their superior performance, however, the strongly asymmetric beam profile along the fast and slow axes presents a big challenge in the beam shaping of EEL. Traditional optical devices mainly focus on adjusting the asymmetric divergence angle of the fast and slow axes of the EEL, and it is difficult to achieve flexible and precise control of the luminous distribution of the EEL due to the limited freedom of the conventional beam-shaping elements. In this article, we employ freeform lenses to flexibly reshape EEL beams and develop an approach to tackle the obstacles caused by the strongly asymmetric beam profile by generalizing the Monge– Ampère method to tailor freeform beam-shaping lenses for EELs. Three typical but challenging beam-shaping tasks show that both the intensity and wavefront of an EEL beam can be reshaped in a desired manner by the use of a single compact freeform lens without any symmetric restrictions on the architecture of the beam-shaping system.

Flat-top beam is widely used in laser applications such as holography, material processing, and nuclear fusion. However, it is difficult to maintain the flat-top effect over long distances due to the limitations of wavefront modulation and natural diffraction effects. This study aims to shape a circular Gaussian beam into a canonical flat-top beam and preserve its flat-top characteristics during long-distance (meter-level) transmission. Based on the principle of energy conservation, an energy mapping relationship between the incident plane and the output plane is constructed, and a circular flat-top intensity distribution is obtained at the output plane. The wavefront quality of the outgoing beam is controlled by the principle of equivalent optical length between mapping point elements. An off-axis reflective free-form surface optical shaping system is designed. The incident Gaussian beam has a spectral range of 1060±15nm, a beam waist diameter of 40mm, an energy truncation diameter of 60mm, and a beam quality β of 3. After the shaping system, a flat-top beam is shaped at the position of 5m output plane behind the mirror. The energy uniformity is more than 95% and the energy utilization rate is more than 90% within the diameter of 60mm. The flat-top effect can be maintained within 10m. The results show that this system can effectively shape and transmit a flat-top beam over long distances. This study provides a novel and practical method for flat-top beam shaping and transmission, which has potential applications in various laser fields.

When specifying optical surfaces of complex shape, polynomial representation methods are often used. However, if the equation of the curve is not described by a standard polynomial, the approximation error at the edges of such functions increases sharply - this introduces huge oscillations. Freeform surfaces of a complex geometric representation are achieved often as a result of design of beam shapers. Spline methods allow minimizing the effect of oscillations after the surface approximation of the beam shapers. In this paper, a comparative analysis of methods for approximation of freeform surfaces is given using the example of Focal-piShaper synthesis and single collimating lens with one freeform surface. The approximation results for the Focal-piShaper prove the high efficiency of the spline approximation, while in the case of aberration-free collimating lens it is preferable to use polynomial regression.

Freeform optical components are increasingly demanded by optical manufacturers and researchers, and are always a challenging topic for metrologists. Form errors of the freeform surfaces resulting from the manufacturing process are critical, in terms of the functionality and reliability of the freeform optics. This paper presents two methodology case studies of off-axis aspheric optics using contact profilometry and non-contact scanning point interferometry. The contact method is accomplished by use of an ultra-low noise measurement platform, combined with a patented phase grating interferometry (PGI) technology and specially developed algorithms for calibration and analysis. The study shows the capability of the proposed method for high tangential slope freeform measurement. This slope measurement capability of PGI Freeform, together with its large gauge range, enables 3D form measurements for most freeform surfaces. However, for some optical surfaces non-contact measurement is preferred due to the possible surface damage caused by the stylus force of contact method. Non-contact scanning metrology is based on a patented multi-wavelength interferometry (MWLI) technology. It provides high density 3D data in short measurement times at a highly reproducible form measurement accuracy. The long-range absolute measurement capability of the MWLI sensor, together with its ultraprecision metrology platform and improved calibration routine through which the sensor accurately follows the designed shape of optical surfaces, enables precise 3D freeform surface measurements within its tangential slope measurement range.

When the missile is flying at high speed, the surface shape and refractive index of the conformal dome will change due to the aero-optic effect, which results in different image quality at different flight times. Hence, it is of great significance to study the influence of flight time on aero-optical imaging quality degradation of the conformal dome. Taking an airto- air missile as an example, this paper uses Zernike polynomials, image simulation, and peak signal-to-noise ratio (PSNR) to evaluate the degeneration of the aero-optical imaging quality of an ellipsoid dome with a flight time range of 0-10 s under varying conditions. The simulation results show that, with the increase of flight time, (1) the dynamic range of tilt, defocus, astigmatism, and coma increase; (2) the PSNRs of the simulated images decrease. Therefore, the effect of flight time on the aero-optic imaging quality degradation of the ellipsoidal dome is gradually serious.

Metasurfaces can overcome the shortcomings of traditional lenses, such as large volume, heavy weight and difficult aberration correction. However, based on the diffraction principle, metasurfaces have serious chromatic aberration and lower efficiency than traditional glass lenses, so they need to be used with monochromatic laser illumination. Therefore, metasurfaces are the best choice for lidar systems to realize miniaturization and lightweight design. The lidar emitting system usually uses a 905nm pulsed laser diode (PLD) as the light source, which requires two cylindrical lenses to collimate the laser beam in the X and Y directions separately. In this paper, two metasurfaces is designed in different areas of the same substrate to collimate the laser beam. By folding the light path through the right-angle prism, the beam passes through two metasurfaces successively, which are responsible for collimating the rays in the X and Y directions respectively. After collimation, the divergence angles of the rays are less than 0.3°×0.1°. By attaching a microelectro-mechanical system (MEMS) mirror behind the metasurfaces to realize scanning, we can obtain the lidar emitting system. By using metasurfaces to replace the traditional cylindrical lenses, the weight and size of the lidar emitting system can be greatly reduced. With further research on metasurface technology, metasurfaces are expected to replace the traditional lenses and even the scanning device in lidar, so as to realize highly integrated chip-level lidar.

Transient measurement technology has broad application prospects in fields such as mirror processing, automotive painting, and precision mechanical processing. It can help us monitor and analyze instantaneous changes in the processing process in real-time. The existing contact and non-contact measurement methods have drawbacks in both non-destructive testing and transient measurement directions. This paper develops a transient measurement system for color speckle deflectometry, aiming to improve efficiency in the field of optical measurement. The core components of the system described in this paper include a liquid crystal display (LCD) screen, a camera, and a beam splitter. By using multi-channel speckle fusion and color correction, one color image is captured to achieve the same effect as the previous three monochromatic images. The gradient of each point on the surface under test (SUT) is obtained through speckle shift, and then the surface shape of the SUT is obtained through integration. The feasibility is verified by the actual measurement with a flat mirror. By utilizing these devices and methods, transient measurement of the three-dimensional shape of a mirror can be achieved, and reliable results can be obtained in both laboratory environments and processing sites. Compared with traditional measurement methods, this system not only has a significant improvement in measurement speed, but also can achieve non-destructive and in place measurement.

Traditional phase retrieval methods for Ronchi lateral shearing interferometry eliminate the impact of high diffraction orders by increasing the number of phase-shifting interferograms, however, this introduces additional error in the phase-shifting process. We propose an optimization method combining a 2-frame phase-shifting algorithm to achieve accurate wavefront reconstruction. A numerical model matching the physical model is constructed and the cross-iterative gradient descent method is used to optimize the initial results obtained by the two-step phase-shifting method. The accuracy and robustness of the method are verified by simulations and experiments. The proposed method has the advantages of achieving high-precision wavefront reconstruction and correcting the phase-shifting errors, and it significantly simplifies the process of phase shift.

Ultrathin non-diffracting light sheets are crucial for light sheet fluorescence microscopy to provide near-diffraction-limited resolutions over a large field of view. Non-diffracting beams such as Bessel or Airy beams generate semi-uniform LSs that feature wide span ranges but often come with strong sidelobes or increased thickness. Moreover, they require scanning, extensive adjustments, and are costly. Through computer simulations, we show here that it is possible to generate quasi-non-diffracting static light sheets with suppressed side lobes in a simple and efficient fashion. This is achieved by placing a multiple slit interference mask (MSIM) on a cylindrical lens. As the name MSIM implies, our technique merely relies on the well-known physics of multi-slit interference to engineer light sheets. Simply dialing the mask’s geometry enables us to generate sidelobe-free light sheets with limited length or ones with a longer length but a broader thickness. This new technique promises to be adaptive in various in vivo and in vitro imaging configurations since we can engineer the light sheet, i.e., make it smaller or larger depending on the needed resolution, the size of the field of view, and the optical properties of the biological sample. This development holds significant potential for advancing microscopy techniques and facilitating groundbreaking discoveries in various biological and biomedical research fields.

As a snapshot 3D imaging technology, light field imaging is able to obtain the 3D information of objects in a single exposure and widely used in numerous fields. The paper analyzed the 3D imaging principles of defocused light field camera and elaborated the relationships between its performance indexes and structural parameters, then a performance index system of defocused light field camera was established. An image-telecentric optical system of defocused light field camera with wavelength range of 0.4-0.9μm, field-of-view of 24.5°, F-number of 5 was designed detailly. Aimed at the lack of a unified image quality evaluation method for defocused light field camera, it was proposed to add pupil aberration as an additional evaluation index on the basis of classical image quality evaluation. The result indicates that the designed defocused light field camera achieved excellent image quality and all indexes met the requirements.

Electrically tunable metasurfaces have great potential for flexible response and high precision in wavefront control, making them highly applicable. However, there is currently a scarcity of electrically tunable metasurfaces working at visible wavelengths. An electrically tunable transmission metasurface working at 660nm was proposed in this paper. The metasurface integrates a transparent conductive oxide material ITO as a tunable electro-optical material. The design scheme of the electrically tunable metasurface is based on the classical Drude model. In the electric field, the variation of carrier concentration in the accumulation layer induced by bias voltage can enhance the nonlinear optical response and improve light field modulation effect. The proposed metasurface is structured with four symmetrically distributed rectangular patches nested with a circular ring. In addition, the phase modulation capability of this model has been theoretically analyzed. With a bias voltage of -4.9V~20V, a continuous transmission phase delay between 0°~191.45° at a wavelength of 660nm can be achieved. The proposal of the electrically tunable metasurface structure establishes a new means for transmitted beam wavefront shaping and modulation, and in the future, the metasurfaces designed with a continuous phase modulation at visible wavelength will suggest more applications in naked-eye 3D display, holographic imaging, and other fields.

In view of the problems that the existing subwavelength transmission grating structure parameters require high processing technologies and are difficult to prepare, this paper explores and investigates the design simulation of encapsulated grism grating based on the finite element method (FEM). The variation of diffraction efficiency and polarization sensitivity of encapsulated grism is explored for different groove structures, trench depth and duty cycle, according to the requirements of high diffraction efficiency and low polarization sensitivity. The grating surface etched onto a fused silica substrate is formed by binary structure of grooves and trenches filled by a high refractive index multi-layer coating, working at Littrow configuration in the SWIR-1 (1590-1625nm) and SWIR-2 (1635-1670nm). The simulation results show that the average diffraction efficiency exceeds 85% and the polarization sensitivity is less than 5% with a wide tolerance range when the depth-period ratio is about 2 and the duty cycle is around 0.6. The diffraction efficiency and polarization sensitivity meet the design requirements, substantially improving the efficiency of transmission grating design and processing. This enables compact optical design to achieve high signal-to-noise ratio and low stray light to meet the critical radiation measurement accuracy requirements.

The study of an in-line NIR multichannel spectrophotometer system is performed in terms of energy efficiency and uniformity of dynamic range in the fiber-optic bundle. Recommendations for choosing an optical design between the afocal and focal probing systems are formulated based on comparison of reflection and transmission operation principles as well as determination of working wavelength ranges and analysis of spectral characteristics of the entire system, from source to receiver. In result, for the afocal system, uniformity of 0.09 was achieved with an energy efficiency of 30.4 percent. A spectrophotometer with a combination of the focal forming system and sapphire windows in a flow cell can achieve a power variation coefficient of 0.165 with a power efficiency of 15.3%.

Tyramine plays a very important role in the proper gastrointestinal function of the human body. By detecting tyramine concentrations, it can be inferred whether the human body is performing normal activities. In this paper, a fiber optic biosensor based on a cladding-offset structure (COF) is proposed to measure tyramine solution at various concentrations. The evanescent field around the probe sensing region is enhanced by etching the probe sensing region with hydrofluoric acid. Due to the large surface area of the gold nanoparticles (AuNPs), likely to occur in the surface chemical reaction, which can be used to capture and recognize tyramine molecules. Therefore, AuNPs are immobilized on the surface of COF to further improve the sensitivity of the tyramine sensor probe. Tyrosinase enzyme is used to enhance the sensitivity of the sensor probe. The performance of the COF fiber sensor is tested by analyzing the transmitted intensity of the sensor. The experimental results demonstrate that the COF-based biosensor provides a good strategy for clinical applications.

Zoom system is an optical system of which the focal length can be changed continuously within a certain range, while the image plane keeps stable and the image quality remains good. Zoom system usually consists of fixed group, variable group and compensation group. However, designing a zoom system can be a complex task due to the large number of variables involved in the optical design. One of the critical challenges is to obtain an effective initial structure of the zoom system. In this paper, a design method based on Delano diagram is proposed to establish the first-order model for the initial structure of the zoom system, which describes the relationship between the zoom ratio, focal length, and other parameters. On the basis of the model, the first-order merit function of the zoom system is analyzed and derived. By controlling the merit function with the help of the algorithm optimization, the first-order solution for the initial structure of zoom system is obtained and can be used for subsequent optimization. In order to further prove the effectiveness of the initial structure, the first-order solution is converted into an actual lens according to the properties of the zoom system. After further optimization, a zoom system with good image quality is obtained, which indicates that the initial structure of the zoom system is of great optimization potential. The final result shows that the design method proposed in this paper provides a helpful approach to solving the problem in obtaining an effective initial structure of the zoom system.

In order to improve the accuracy of the traditional laser tracking interferometric length measurement method and make the traceability of the datum ruler more reliable, a datum ruler measurement optimization method under multi-attitude is proposed in the paper. The method firstly constructs a multi-attitude datum ruler layout on the basis of traditional laser tracking interferometric length measurement, and collects the measurement information in different datum ruler directions under the layout by a laser tracker, and then adopts the weight-based optimization strategy to optimize the combination of measurement data, and then outputs the measurement results and carries out the analysis of the error source and the evaluation of the uncertainty, and finally conducts experimental analysis on the datum ruler with an accuracy of 1000mm based on the optimization scheme. Finally, based on this optimization scheme, an experimental analysis is carried out on the 1000mm datum ruler, and compared with the CMM method with higher accuracy, the En value is 0.1, which verifies the reasonableness of the uncertainty assessment, and it is found through experimental comparisons that the reference lengths output from the measurement optimization scheme with multiple postures are more reliable than those with single postures. The optimization method provides a new calibration scheme for achieving the traceability of the measurement value of high-precision large-size reference ruler, which has good practicality and certain guiding significance.

The paper gives a detailed description of the program VietGOS for automatized synthesis of two-lens and three-lens lenses based on the theory of third-order aberrations. With its help, the synthesis of high-aperture objectives in the visible and infrared spectrum regions and 4-color superachromate was carried out. This program helps an optical engineer to significantly simplify and speed up the synthesis process of two-lens and three-lens objectives with the required characteristics.

In recent years, deep learning-based methods for motor imagery EEG classification have become increasingly popular in the field of brain-computer interfaces. However, most of the studies tend to use sequence-structured classification networks to extract spatial features when dealing with motor imagery EEG signal classification tasks, ignoring the fact that EEG signals as time-series signals contain rich temporal information and features between neural network layers, resulting in poor classification performance. Therefore, this paper proposes a feature fusion network called ResCNNBiGRU, which consists of ResNet-based residual convolutional neural network (ResCNN) and bidirectional gated recurrent unit (BiGRU) connected in parallel. The two branches use different forms of EEG signal feature representation as input, the input to the ResCNN branch is a wavelet transformed time-frequency image, and the input to the BiGRU branch is EEG data in a two-dimensional matrix format. ResCNN extracts spatial features and utilizes interlayer features through residual connections. It also introduces convolutional block attention module (CBAM) to avoid introducing too much useless low-level feature information during interlayer feature fusion. BiGRU extracts temporal features. Finally, experiments are conducted on the authoritative four-category motor imagery dataset BCI Competition IV 2a to verify the performance of the proposed algorithm.

In dual-wavelength interferometry, how to accurately separate single-wavelength interferogram from a dual-wavelength interferogram and retrieve the high-precision phase distribution from a single frame interferogram is a critical problem. In order to solve this problem, a single frame dual-wavelength interferogram modulation method based on deep learning strategy is proposed in this paper. Dual-wavelength network (D-Net) and Phase network (P-Net) are proposed in this study. The method only requires a single frame dual-wavelength interferogram. With a well-trained D-Net network, the interferograms corresponding to the two different wavelengths can be extracted from the single frame dual-wavelength interferogram respectively, and are taken as the input of P-Net. P-Net outputs the wrapping phase of the two wavelengths, and then the dual wavelength phase can be obtained by unwrapping the wrap phase. Finally, the tested optical element surface shape can be obtained from the phase distribution. Furthermore, instead of using real experimental data, an interferogram generation model is constructed to generate the dataset for the network’s training. The learning rate attenuation strategy adopting appropriate optimizers and loss functions is introduced to guarantee the high-accuracy training of the network. Simulations have been done to validate the feasibility of this algorithm. The simulations prove that this method can guarantee a high detection accuracy and expand detection range, which provides a solution for the phase recovery problem in dual wavelength interferometry.

The fast development of IOLs has provided patients with optical performance that more closely resembles that of the healthy human eye, however such optical performance experience is achieved only for on-axis (0 degrees) optical performance, leaving the peripheral vision inferior to the health human eyes.. Recently, studies have demonstrated the importance of peripheral vision to patients' daily life. To solve this problem, an IOL with improved peripheral vision has been proposed. The IOL is designed to optimize peripheral vision in a 40-degree field of view (FOV) under 3 mm pupil diameter, while maintaining on-axis optical performance. The design results shows that the designed IOL provide the same level of central field optical performance compared to healthy human eyes and traditional IOLs as well as the improving peripheral vision. This IOL design may help to reduce the risks related to peripheral vision loss in daily life.

Among current true 3D display technologies, multi-layer 3D displays based on the principle of compressive light field have the advantages of high resolution, simple structure and faithful restoration of depth cues, demonstrating enormous research value and application potential. In recent years, multi-layer 3D displays have attracted increasing attention from researchers and some progresses have been made in improving the performance. However, there are still some limitations, such as the color deviation issue which causes unnatural colors of the reconstructed scene. In this paper, we propose using a customized look-up table (LUT) to alleviate the color deviation problem of multi-layer displays. For each of the display layers, we measured the response curves of the RGB channels, respectively, corresponding to different input gray levels. Then we compared them with a commercial standard display, so that we could correct each value within the gray range of the three channels to obtain a target output response, and the corrected values were used to build the look-up table. Using the customized LUT, we successfully achieved correction of color deviation in our multilayer display system. Finally, we demonstrated a 3D scene with natural colors, proving the effectiveness of our method on correcting the color deviation in multi-layer light field displays.

Optical systems with high tolerance sensitivity can be significantly affected by errors in manufacturing and assembly. By discussing the change in the ray position on the image surface caused by the system tolerance, we propose a scheme by controlling the change of the chief ray on the image surface as little as possible with the chief ray drift, which is called the stability of the chief ray, to reduce the tolerance sensitivity. The effectiveness of the method is demonstrated by a design example. Since it is based on controlling the real rays of the optical system, this method can theoretically be applied to all optical systems design.

The operation of an optical system in a wide spectral range is an essential characteristic of modern research instruments. This is especially true for systems for studying objects, access to which is difficult or short-term. Work with such objects often takes place in conditions that are far from laboratory ones, including temperature differences, which at certain values make it unacceptable to use cemented optical elements. In turn, cemented doublets are a classic of chromatic aberration correction, which are the larger, the wider the required spectral range. The paper describes approaches to the selection of glass combinations for optical systems operating in the spectral range of 0.3…1.06 μm for temperature ranges of 5 °C…45 °C, -10 °C…50 °C, -50 °C… 80 °C. Linear expansions of materials and chromatic aberrations correction methods are studied. The results were obtained due to design experience of a wide-spectrum lens with a focal length f'=20 mm and F/# of 6.

Soft X-ray free-electron lasers (FELs) have gained significant attention as a research tool in X-ray ultrafast spectroscopy due to their ultra-high pulse brightness and ultra-short duration. Combined with an independent optical laser to perform pump-probe experiments with time resolution has wide-ranging application value and can have great impact on ultrafast dynamics research in fields such as energy catalysis, solid state physics, materials science, and biology. However, the inherent temporal and spatial jitter of soft X-ray FEL pulses significantly limits the time resolution in these experiments due to the low level of synchronization between the two independent light sources. Here, we present a spatiotemporal coupling device suitable for soft X-ray FELs. The device uses a self-designed four-blade slit device which is suitable for ultra-high vacuum environments to complete the spatial coupling between the two foci of both the soft X-ray FEL and optical laser, reducing the negative effects caused by spatial jitter of soft X-ray FEL beam spots. Based on this, a wavefront-splitting scheme is used to reflect and separate approximately 30% of the soft X-ray FEL beam for arrival time diagnosis. Based on the principle of transient decrease in the reflectivity of semiconductor material surfaces induced by X-rays, precise time measurement is achieved on a shot-by-shot basis through spectral encoding. After experiments, the data is rearranged according to the arrival time delay between the two pulses, effectively increasing the time resolution of the pump-probe experiment to the femtosecond scale.

The prevalence of myopia has increased worldwide. One of the effective ways to control myopia progression is specially designed spectacles. However, the optical performance of the eye wearing such spectacle lenses were rarely reported. This study presents a spectacle lens design for myopia control along with optical performance analysis. The spectacle lens has an optical zone of 9 mm in diameter, surrounded by lenslets located in a circular zone from radial distance of 4.5 mm to 17 mm. The lenslets are arranged in the form of a Fibonacci spiral. The optical structure of the spectacle lens was built in the design software Zemax. The peripheral refraction (M, J0, J45) of the eye wearing designed spectacle lens was calculated and compared with results from the eye wearing spectacle lens with lenslets arranged in the same way as the two commercially available spectacle lenses. Additionally, the MTF (Modulation Transfer Function) of the eye with rotation was calculated as well. The results show that the myopic defocus within the ±40° field of view as well as MTF during eye rotation are higher than these of the other two types of lenslet arrangements, demonstrating that the new spectacle lens may control myopia progression more effectively and provides a better visual quality when the line of sight deviates from the center of the lens.

Imaging systems consisting of flat phase elements can achieve more compactness and lighter-weight. In this paper, we propose a design framework of off-axis reflective imaging system consisting of flat phase elements based on deeplearning. Differential ray tracing for off-axis systems consisting of flat phase elements is used. Supervised and unsupervised learning are combined to improve the generalization ability of the deep neural network for a wide range of system and structure parameter values. Single or multiple systems can be generated directly after the design requirements are inputted into the network, and can be taken as good starting points for further optimization. The design efficiency can be significantly improved, and the dependence on the advanced design skills is dramatically reduced.

With the explosive data growth over internets and communications, traditional optoelectronic switching technologies meet many challenges, such as the lower switching speed, insufficient capacity and excessive power consumption et al. The optical interconnect technologies have developed and present very good advantages, e.g. the expanded bandwidth, high switching speed, low energy consumption, small sizes and high integration. Optical switch is a kind of very critical components for optical interconnect technologies. In this paper, we propose a mode multiplexing 1×4 waveguide optical switch structure, which is a silicon based integrated switch with non-volatile chalcogenide optical phase-change material (C-OPCM) thin films. The optical mode transmission characteristics of the switching paths analyzed and calculated by the supermode coupling theory. The optical switch device is theoretically modeled and analyzed by using a threedimensional finite-difference time-domain (3D-FDTD) method. The 1×4 optical switch device can transmit different optical modes by switching different phase states of C-OPCM films. As inputting a TE0 mode, the outputs are four different order modes of TE0, TE1, TE2, and TE3. Different switching channels select different transmission modes. Such a 1×4 optical waveguide switch presents low insertion losses (ILs) and relative high extinction ratios (ERs). The insertion losses are respectively as low as 0.7 dB, 0.27 dB, 0.15 dB, and 0.54 dB for TE0 mode at output portO1, TE1 mode at output port O2, TE2 mode at output port O3, and TE3 mode at port output O4. The extinction ratios are separately as high as 20.3 dB, 23.29 dB, 17.55 dB, and 18.63 dB . This kind of phase-change optical switch devices exhibit excellent transmission characteristics, non-volatility, and smart structures and high integration, which have potential application values in the fields of photonic integration and photonic networks.

Currently, most space-borne optical cameras have fixed focal length and depth of focus. In this case, the range within which the target can be clearly imaged has been pre-determined before launch. However, the distance of the target to the optical camera might be unknown or change very fast and therefore focus adjustment has to be carried out to obtain clear images. However, no matter which refocusing technique is used, focus adjustment might lag behind the object distance variation and depth of focus extension is a better way. Wave-front coding can be used to extend the depth of focus of incoherent imaging system but the surface profile of the phase mask could not be changed dynamically, which is not flexible for application. In this manuscript, by combing the variable curvature mirror (VCM) and coded imaging technique together, a new depth of focus extension technique is proposed. According to our previous studies, the focal plane could be quickly adjusted by changing the curvature radius of VCM. Compared with the curvature variation speed, the exposure time of the camera is quite long. Therefore, by adjusting the focal plane very fast in a wide range during the exposure through VCM, an equivalent coded optical transfer function having no null frequency points within bandwidth is generated and the image captured is uniformly blurred. After that, with the help of digital restoration, the clear image could be obtained. Because the focal plane could be adjusted through variable curvature mirror in the range of millimeter, the proposed method could be used to obtain clear images with greatly extended depth of focus.

MUltiplexed Survey Telescope (MUST) proposed by Tsinghua University aims to build a 6.5-meter widefield telescope for the ground-based spectroscopic survey. MUST adopts the Ritchey-Chretien system with the Cassegrain focus, consisting of an active support primary mirror, a passive support secondary mirror and a multiple-element widefield corrector. In order to fulfill the needs of the widefield spectroscopic survey, the primary mirror is supported in a specific approach rather than traditional methods, which results in optical distortions in the center region of the beam. In this paper, we presented a self-compensation method using the corrector itself to compensate the optical distortion caused by the primary mirror. Based on the optical system of MUST, an optical model of the self-compensation is established, and numerical simulation is conducted to implement the optimization of the corrector and investigate the self-compensation ability. Simulation results indicate that the surface shapes of the elements inside the corrector could be evolved to realize the self-compensation through the optimization of the widefield corrector, including the materials, surface shapes and load conditions. By using the presented self-compensation method, the optical distortions are well compensated and the image quality at the focal plane could be effectively improved.

Illumination of the object of study is an important part of the research by optical methods. In some devices, it is necessary not only to illuminate the object of study completely, but also to achieve uniform illumination. To do this, in such optical systems as biological microscopes, an illuminating optical system of the Köhler type is used. Modern research in the field of improving the classical Koehler scheme has shown that they are aimed at improving the optical and energy characteristics, and do not take into account the dimensions of the lighting system. In some new models of microscopes, to reduce overall dimensions, only an LED with a frosted diffuser is used as an illuminating optical system, providing complete, but not uniform, illumination of the object. In this work, an illuminating optical system with reduced overall dimensions was developed. The stages of calculation of the collector and condenser of the lighting system are shown.

The MUltiplexed Survey Telescope (MUST) is a 6.5-meter aperture wide field spectroscopic survey telescope built by Tsinghua University. In the optical system of MUST, the second mirror is designed as a hyperbolic flat-convex reflector with an effective aperture of 2.4 meters. In order to achieve high imaging quality under different zenith angles, lightweighted mirror structure is adopted to effectively reduce the weight of the secondary mirror and depress the deformation of the surface figure. In this paper, a preliminary finite element model of the second mirror with multi-point passive support is established and numerical simulation is utilized to investigate the effects of different light-weighted schemes. In the simulation, parameters of the mirror structure are taken into consideration, including the distribution and the structural forms of the light-weighted holes, the back plate and the rib, and the distribution of the passive supports. According to the optimization results, a light-weighted secondary mirror with 36-point axial support is finally achieved to significantly reduce the weight by more than 70% and effectively improve the surface accuracy to 20nm RMS value. To our best knowledge, this is one of the largest aperture light-weighted secondary mirror with passive supports and the presented light-weighted design could provide a reference for the future development of 2-meter class secondary mirror.

MUltiplexed Survey Telescope (MUST) proposed by Tsinghua University is a 6.5-meter widefield telescope for the ground-based spectroscopic survey. To realize the design target of large field of view of 7 square degrees, the effective aperture of the secondary mirror is preliminarily designed to be 2.4 meters, and the mass of the secondary mirror assembly is supposed to be about 3 tons. Under different zenith angles, the attitude variation of the secondary mirror assembly will affect the stability of the optical axis and result in the spot drift of the focus image on the focal plane. In this paper, a simulation model of the top end assembly is established. Finite element analysis is carried out to investigate the effects of different parameters of the top end assembly on the performance of the optical system, including the vane horizontal offset angle, the vane altitude offset angle, and different forms of ring assembly. Based on the simulation results, an optimized top end assembly is preliminarily obtained and the magnitude of spot drift on the focal plane could be effectively limited at different zenith angles and field of view (FOV).

An incoherent optical cryptosystem based on hybrid wave aberration is proposed in this study. The proposed cryptosystem is designed with different channels to divide the object. In each channel, different wave aberrations are allocated to form the hybrid wave aberration. When the object is imaged by the channel with huge wave aberrations, its corresponding image will be blurry enough to form a ciphertext. Because the different wave aberrations in different channels can be regarded as the key, the proposed optical cryptosystem can achieve multi-key encryption as well as local encryption. The proposed optical cryptosystem enhances the security of incoherent optical cryptosystem through the quantity of keys and the special construction method of ciphertext.

Ghost images, as a form of stray light, are caused by the even reflection of residual reflected light between the optical surfaces of the system. Ghost images can seriously reduce imaging clarity, annihilate targets, and seriously affect the performance of optical systems. The Modulation Transfer Function (MTF) is a parameter used for evaluating the imaging quality of optical systems, but traditional MTF cannot reflect the impact of ghost images on the imaging quality of optical systems. In order to investigate the impact of ghost images on the performance of imaging systems, a calculation model for modulation transfer function (MTF) under the influence of ghost images generated by secondary reflections was constructed, and an example verification was conducted on a system. The verification results showed the effectiveness of the calculation model.

Anamorphic optical system has double-plane symmetry. it’s focal length in the two symmetry planes are different. The anamorphic optical system can obtain a wider field of view when using sensors of conventional size. Based on the firstorder aberration characteristics of anamorphic optical systems, a method for designing anamorphic optical systems is proposed in this paper. An anamorphic optical system is designed by using Biconic Surface.

With the development of optical systems to improve the detection accuracy of polarization aberration brings more and more problems, affecting the polarization detection accuracy of the system as well as the imaging contrast, so it is necessary to quantitatively analyze and calculate the polarization aberration. The polarization aberration distribution of a refractive anamorphic optical system is analyzed using a three-dimensional polarized light tracing method. Calculating the distribution of diattenuation and phase retardance for each face type yields a maximum diattenuation of 0.145 and a maximum phase retardance of 1.46x10-2rad both occurring in the second reflector. In addition the Jones pupil and amplitude response matrices of the system were calculated, ghost psf for this deformation optical imaging contrast was limited to the order of 10^-6.

The optical performance of a panoramic annular lens (PAL) might be severely deteriorated by stray light due to the catadioptric optical structure and the ultra-large field of view (FoV). A comprehensive research on stray light in PAL systems with experimental validation is carried out. The fundamental cause, forming light path, impact on the image plane, and first-hand solutions of all visible types of stray light are obtained and discussed. By analyzing some specific light paths, we also introduce the prerequisite of a real-time evaluation and suppressing algorithm for stray light in a PAL system that purely operates in optical design software.

We propose a single-sensor gazing panoramic stereo imaging system with no central blind area based on polarization technology. This solution addresses the issue of traditional stereo panoramic systems, which often feature large and complex mirrors in front to reflect light. Drawing inspiration from the traditional dual-channel structure, we apply polarization technology to the first reflective surface, creating a third channel for stereo vision. Our system demonstrates a promising approach to achieving stereo vision without the need for additional complex structures on the original basis.

Phase retrieval (PR) technology can reconstruct the complex amplitude information of the entrance pupil surface from the captured defocus intensity images, and has been successfully applied in many scientific fields such as astronomical observation, biomedical imaging and digital signal restoration. For low numerical aperture (NA) optical systems, the point spread function (PSF) can be calculated using the Fresnel diffraction propagation theory based on Fourier transform, ignoring the polarization field of the light field. However, for high-NA systems, the focal spot not only includes the transverse component, but also the longitudinal component accounts for a proportion that cannot be ignored, thus necessitating a vector model when calculating the PSF in the non-paraxial region. In this paper, the vector diffraction calculation model with arbitrary defocus distance based on the extended Nijboer-Zernike (ENZ) theory is established, which can characterize the light field components in three directions under the Cartesian coordinate system. What’s more, a modified Gauss-Newton theory is innovatively applied to the axial phase difference PR model. Compared with the traditional first-order algorithm, the second-order algorithm can reduce the number of iterations. In addition, so as to verify the effectiveness of the proposed method, numerical simulations matching the physical model are carried out, the results show that the proposed method can accurately reconstruction the wavefront with high robustness. In conclusion, the established vector PR model in this paper would provide a creatively guidance for wavefront measurement of high-NA optical systems that is significant in the fields of semiconductor lithography, micro imaging and micro manipulation.

High-power single-mode laser diodes around 795 nm are widely used in applications such as Rb atomic clocks and nuclear magnetic resonance imaging. We simulate a high-power single-mode semiconductor laser around 795 nm based on a supersymmetric structure. In the lateral direction, the mode stability characteristics are investigated by varying the three waveguides widths and the distances between the middle main waveguide and the two sub-waveguides. Since the left and right waveguides have different widths, the optimal distance from them to the main waveguide is also different. In order to ensure the single-mode operating of the laser, there is a pair of optimized distances from the left and right waveguides to the main waveguide. The distances from the left and right waveguides to the main waveguide are 1 μm and 1.2 μm, respectively, when the widths of the left waveguide, right waveguide and main waveguide are set as 2.3 μm, 3.5 μm and 6 μm, respectively. In the longitudinal direction, a laterally-coupled grating structure is used to achieve longitudinal mode selection. Such lasers are expected to be the next generation of high-power, narrow-linewidth, singlemode laser diodes.

The grating lateral-shear interferometry has a wide range of applications in wavefront sensing. The lateral-shear interferometer based on Ronchi grating can be applied for high-precision wavefront aberration detection of lithography projection lenses, which is one of the critical issues to overcome lithography challenges. The conventional Ronchi shearing interferometer object grating consists of two sets of one-dimensional Ronchi grating lines perpendicular to each other in order to obtain wavefront information in two directions, namely X and Y. During the experiment, one set is moved into the optical path for phase shifting and measurement, then the other set of grating lines is repeatedly operated. To reduce the complexity of experimental operations, this paper proposes a lateral-shear interference system based on double checkerboard gratings. The object grating and image grating are both set as checkerboard grating, and the rotation angle of the checkerboard grating varies according to the optical system's shear rate, allowing each phase shift to obtain wavefront information in X and Y directions. Multiple uniform phase shifts are performed to extract ± 1 order diffraction wavefronts of X and Y directions. The shear wavefront of the optical system to be measured is calculated from the four-wave interference light field, then the original wavefront can be restored by differential Zernike. Through theoretical analysis and simulation, this double checkerboard system can achieve wave aberration measurement with the same accuracy as traditional Ronchi interferometers, improving the real-time performance of projection lenses wave aberration measurement, and providing more possibilities for subsequent structural improvements of Ronchi lateral-shear interferometer.

In recent years, the use of freeform optical surfaces in optical system design has experienced a significant increase, allowing systems to achieve a larger field-of-view and/or a smaller F-number. Despite these advancements, further expansion of the field-of-view or aperture size continues to pose a considerable challenge. Simultaneously, the field of computer vision has witnessed remarkable progress in deep learning, resulting in the development of numerous image recovery networks capable of converting blurred images into clear ones. In this study, we demonstrate the design of offaxis freeform imaging systems that combines geometrical optical design and image recovery network training. By using the joint optimization process, we can obtain high-quality images at advanced system specifications, which can be hardly realized by traditional freeform systems. We present a freeform three-mirror imaging system as a design example that highlights the feasibility and potential benefits of our proposed method. Zernike polynomials surface with an off-axis base conic is taken as the freeform surface type, using which the surface testing difficulty can be controlled easily and efficiently. Differential ray tracing, image simulation and recovery, and loss function establishment are demonstrated. Using the proposed method, freeform system design with increased field-of-view and entrance pupil size as well as good image recovery results can be realized. The proposed method can also be extended in the design of off-axis imaging systems consisting phase elements such as holographic optical element and metasurface.

Identifying the cause of aberration in general optical systems is difficult and time-consuming because it requires specific measurement and analysis. Therefore, we suggest a novel method based on deep learning to find out misalignment numerically from measured raw images at near-focus, that do not require specific measurements, without the time and effort of analysis. Taking advantage of deep learning, which numerically extracts features from images, our model takes a set of distorted images as input and outputs parameters indicating misalignment. We develop two deep learning models to predict the misalignment of optical systems, a parabolic mirror and a telescope, using a dataset generated through simulation. In spite of real measurement images have noise, the trained model for a parabolic mirror can predict misalignment parameter. Near-focus images suggested by the model exhibit the similar trend in PSF size and stretch direction to the measurement images. To elevate our methods to a practical level, we adjust the telescope in accordance with the model’s predictions. This adjustment results in improved symmetry of the images in the front-back focus direction.

The assembly positioning state of the imaging detector has an important influence on the performance of the photoelectric reconnaissance system. The axial positioning accuracy of the imaging detector will affect the imaging clarity and resolution, and the radial positioning accuracy will affect the optical axis consistency of the optical path system. The tilt, translation, rotation and position of the detector will bring multi-dimensional errors during the installation of the imaging detector, resulting in image plane misalignment, image blur and optical axis offset. In this paper, an optical measurement system is designed and built, which can automatically distinguish the installation error of the imaging detector and assist the installation of the imaging detector. The translation installation error is less than 0.015mm, and the rotation deflection error is less than 0.015 ', and the installation qualification can be given according to the clarity of the observation system image.

During the chip manufacturing process, meeting overlay error requirements is essential to semiconductor yield. Measuring equipment of overlay error requires standard samples, which the double-layer grating with precise horizontal alignment can be used as, to verify its capability. Thus, we propose a novel alignment and processing method for layer separated processed double-layer gratings. Firstly, the bottom grating is obtained by holographic lithography . The upper and lower layers are aligned based on the homogeneous period of processing diffraction patten and the bottom grating, and manufactured simultaneously. We conducted an optical simulation of the alignment based on FDTD, setting the bottom grating as Ag material, 50 nm depth, 1μm period, and 50% duty cycle. Principally, the alignment accuracy is comparable with the linear encoder.

Combining adaptive illumination systems with computer vision allows for optimized lighting in various scenarios. In automotive applications, matrix configurations of individually dimmable LED pixels enable automated and adaptive lighting, detecting oncoming traffic and activating specific areas accordingly. Such systems also have potential for general lighting, where cameras detect objects and define a target illuminance distribution. However, illumination applications require smooth light output while realizing the target distribution. This paper proposes a least squares-based method for LED array pixel addressing, resulting in smooth and effective illumination.