This PDF file contains the front matter associated with SPIE Proceedings Volume 12315, including the Title Page, Copyright information, Table of Contents, and Conference Committee Page.

With the advent of high brightness microdisplay, augmented reality head mounted display (AR-HMD) has rapidly developed and applied. Various optical schemes emerge one after another. However, it is still a huge challenge to realize large field of view (FOV), high resolution and keep the compact form of head mounted display. We propose a novel free-form prism tiling optical system, which can simultaneously realize large field of view, high resolution and compact optical see-through augmented reality HMD. It can overcome the FOV/resolution invariant and solves the problem that the optical axes of the display channels don’t coincide with the visual axis of the human eye. The optical system consists of two microdisplays, two free-form prisms and a compensation lens which are attached together. The prisms are partially overlapped to provide the same field of view and reduce the seam at the transition region of adjacent FOV. The optical see-through system we designed achieves large FOV of 52.8°×52.8° (70° diagonally) and resolution of 33.7 pixels/degree, and has good optical performance. We emulated the system with distortion and illuminance pre-conditioning and discussed the remaining problems and future work.

Mini-LED backlight and quantum-dot color conversion (QDCC) technology are the research hotspots of emerging display technology. When they are combined together, the luminance uniformity issue may occur because of traditional QDCC film (QDCCF) with uniform thickness. This paper designs and optimizes QDCCFs with non-uniform thickness of cone and circular truncated cone, respectively. The illuminance uniformity is analyzed by simulation. Results show that the illuminance uniformity of the optimized cone and circular truncated cone with a single structure can reach 73.97% and 74.72%, respectively. The single structure with uniform thickness is only 35.84%. After that, the single structure with nonuniform thickness is arrayed with a basic substrate added at the bottom, which is matched with the mini-LED backlight. By optimizing the array configuration and the basic substrate, the illuminance uniformity of the backlight reaches 73.55% and 79.25%, respectively. This QDCCF with non-uniform thickness distribution can effectively improve the illuminance uniformity when mini-LED is combined with QDCCF. This work proposes a new strategy for uniform color conversion of mini-LED display backlights.

The SiTian project is mainly aimed at a photometric survey of the 10,000 square degrees sky within 30 min in three bands. The telescopes for the SiTian array must have a super-wide field-of-view (FOV). For the optical system discussed in this paper, we have investigated four types of wide-field telescope optics: Cassegrain with correctors, three-mirror anastigmatic, prime focus, and modified Schmidt types. Weighing up the pros and cons, the catadioptric system, transformed from a modified Schmidt telescope, was adapted for the prototype of the SiTian array.

The optics of the SiTian array is a 1 m/1.27 m modified Schmidt optical system, with an aperture of 1 m, an FOV of 7°(25 square degrees), and a focal ratio of 2.06, and is capable of imaging from 400 to 1000 nm. The image scale is 1 arcsec per 10 µm, and the optimal optical performance is 2 arcsec (80% of the encircled energy diameter less than 20 µm), which is suitable for the photometric survey.

Data-driven methods to assist lens design have recently begun to emerge; in particular, under the form of lens design extrapolation to find starting points (lenses and freeform reflective system). I proposed a trip over the years to better understand why the AI have been applied first to the starting point problems and where we are going in the future. In this talk, we will explore to most recent progress applications of DNN in optical and lens design. We will also show some working example and discuss the future.

This paper describes an optical design of a compact continuous zoom mid-wave infrared (MWIR) lens for use with today’s infrared detector technologies. The developed design is applicable in industries where system size becomes a critical factor, including unmanned aerial systems (UAS), unmanned aerial vehicles (UAV) and drone payloads. By applying optical design principles such as power distribution via element bending, element splitting and aberration balancing, a continuous zoom MWIR lens was successfully designed. It has a focal length range of 20–275 mm, which translates to a magnification ratio of almost 14x. The IR detector type that is compatible with the developed design is a VGA (640 x 512) high operating temperature (HOT) MWIR focal plane array (FPA) having a pixel pitch of 15 μm and an aperture of F/5.5. While a standard MWIR FPA is usually sensitive to a spectral range of 3.7–4.8 μm, a HOT MWIR FPA is responsive to a spectral range of 3.7–4.2 μm. This is also the limits which the optical design discussed in this paper was optimized for. Overall, the continuous zoom MWIR lens managed to maintain its high level of imaging performance throughout the prescription zoom range, all of which is contained within a compact package under 100 mm in length. With its long target detection range, the developed design is highly suitable for surveillance UAV payloads as well as other relevant aerial systems on the market.

The paper considers a two-level method of ray tracing in optical systems containing aspherical surfaces. The problem with the methods for finding the point of a ray intersection with an aspherical surface is the absence of an analytical solution for surfaces whose polynomial degree exceeds four. Existing numerical solutions may turn out to be inefficient and require many iterative approximations while fitting the ray to the surface. Also, when performing a stray light analysis, the rays’ directions can differ significantly from the natural path, which leads to a significant loss of accuracy and excess memory load. The current study is aimed at solving two main problems: increasing the efficiency of calculations (decreasing the number of iterations) and increasing the calculation's accuracy. We propose to use a two-level geometry representation for aspherical surfaces. The first level is a triangular mesh approximating the aspherical surface. This mesh is built adaptively, with a specified maximum deviation of the aspherical surface from the mesh faces. The second level is the aspherical surface itself. The intersection with the triangle mesh brings the ray close to the aspherical surface. Then, using information about intersected triangle vertices and normals, an approximation is performed, which significantly speeds up and improves the accuracy of the search for the intersection with an aspherical surface. Using SIMD programming allowed for achieving high performance for tracing beams of rays, e.g., during stray light analysis. The efficiency and correctness of the solution were demonstrated by examples of the point spread function calculations.

Infrared polarization imaging can achieve faster perception speed and higher identification accuracy, which has been widely applied in diverse areas such as space remote sensing, biomedicine, and object detection. Limited by the aperture of the lens, the single-aperture imaging system can hardly meet the needs of high-resolution and multi-polarization imaging simultaneously. Aiming at achieving the properties of high-resolution, high-integration, and multi-channel performance, a sub-aperture infrared polarization imaging system based on freeform surfaces is proposed and demonstrated. The general scheme of the polarization imaging system mainly consists of a common aperture structure, a sub-aperture imaging group, and a relay imaging group. To compress the beam aperture, a Kepler telescope configuration is employed to build up the imaging objective. The field diaphragm is set at the primary image plane to effectively eliminate stray light. Polarizers with different orientations are added to the split aperture imaging group to form four polarization state channels. To reduce the assembly errors of the sub-aperture system, a freeform surface lens is utilized to replace the lens group in the multi-channel. The freeform surface profile uses the "XY polynomial" with eight coefficients. A diaphragm array is arranged on the front surface of the sub-aperture system, which is used to avoid the intersection between the image planes of different channels. To match with the cooled detector, the relay imaging group is designed as a finite conjugate structure with a magnification of -0.44×. The structure allows for simultaneous imaging of four infrared polarization states with the same system, and the MTF of each channel at 33lp/mm is higher than 0.45. Our research satisfies both miniaturization and engineering application requirements.

The off-axis three-mirror anastigmat (TMA) systems are widely used in optical telescopes because of the advantages of non-obscuration and large field of view (FOV). Combined with optical freeform surfaces, which have more optimization degrees of freedom (DOFs), hence with strong ability to correct aberrations, the off-axis TMA system can achieve higher optical performance. However, the off-axis TMA system has the shortcomings of high complexity of assembly and alignment, high error sensitivity, and high cost of manufacturing. Low error sensitivity optical systems, that is, the system has good robustness can resist the errors, reduce image quality degradation, and make the systems easy to achieve good imaging performance and reduce the cost of manufacturing simultaneously. Therefore, desensitization should be given sufficient attention in the design process of optical systems. In order to obtain an optical system with low error sensitivity and improve system achievability, we applied the low error sensitivity design method proposed by our team to desensitize off-axis TMA systems which use freeform surfaces. We compare these off-axis TMA systems with different freeform surface types and give the corresponding analysis, we obtained a freeform surface ranking that is conducive to reducing the error sensitivity in off-axis TMA systems. Using the desensitization design method proposed by our team, the error sensitivity of all the freeform off-axis TMA systems is reduced effectively.

Owing to complex application environments and trends of intelligent perception associated, modern zoom systems with enhanced integration, increased imaging speed, decreased physical size, and improved dynamic adaptive adjustment strategies are required under external disturbances. Upon this requirement, reflective deformable mirrors (DMs, a Micro-Optical Electro-Mechanical System (MOEMS) device), which represent novel optoelectronic devices, have propelled the development of fast zooming and high-resolution imaging systems. In this paper, we design a catadioptric zoom system based on transmission fixed lenses and reflection deformable mirrors. The fixed lenses are used to increase the system field angle, increase the entrance pupil diameter, and balance the off-axis aberration caused by a large field of view. For practical application, we also consider the DMs specifications, e.g., the flexible deformation amount of actuator stroke within the effective diameter range. The system enables continuous zooming in the complete focal-length range at a high zoom ratio (10:1), and the full field of view at the wide-angle position is expanded to 20° × 20°, by improving the zoom sensitivity ability and aberration correction. This optical system is conducive to further establishing a stabilized zoom system with image stabilization ability integrated based on DMs.

Today’s optical design of imaging systems relies mostly on efficient ray tracing and (local or global) optimization algorithms. Such a traditional 'step-and-repeat' approach to optical design typically requires considerable experience, intuition, and sometimes trial-and-error guesswork. Such a time-consuming design process applies especially, but not only, to freeform optical systems. In particular, the identification of a suitable initial design to then adapt and further optimize has often proven to be a laborious process.

We present our developed 'first time right' design method that allows a highly systematic generation and evaluation of directly calculated imaging optics design solutions and thus enables a rigorous, extensive, and real-time evaluation in solution space. The method is based on differential equations derived from Fermat’s principle that can be solved effectively by using a power series method. This approach allows calculating all optical surface coefficients that ensure minimal image blurring for each individual order of aberrations. Such directly calculated optical design solutions can be readily used as starting point for further and final optimization. We demonstrate the deterministic and holistic nature of our method and the streamlined design process for various real-world examples ranging from spherical lens designs to freeform imaging systems. The method allows calculating all optical surface coefficients that ensure minimal image blurring for each individual order of aberrations. We demonstrate the systematic, deterministic, scalable, and holistic character of our method for various design examples ranging from spherical lens designs to freeform imaging systems.

The paper presents an analysis of changes in image quality that occur in optical system with a spectral range shift. A basic system was designed for the visible range with the prospect of receiving objectives operating in the range from UV to IR. In the process of transition from the wavelength of 0,55 μm to 0,2 μm, a dramatic drop for initially diffraction quality system in the Strehl number by 1,5 times was found. However, since this criterion does not represent the features of the image quality drop, both Strehl and other computed image quality parameters (Rayleigh and Marechal criteria) cannot be recommended as universal requirements for systems with an unspecified spectral range. An assessing the multispectral system image quality by MTF is proposed. Based on this, conclusions about the initial requirements for image quality of multispectral systems can be acquired. The conclusions are made based on the experience of designing a Schwarzschild mirror objective with a numerical aperture of 0.8 for the range of 0,21-2 µm.

Composite materials are widely used in aviation, aerospace, and other fields. Poor service conditions, insufficient stiffness or strength of materials and other problems can cause deformation and defects of composite materials, affecting their service life and safety. Optical detection methods can measure composite materials' surface deformation and internal defects separately. However, there is a lack of comprehensive measurement methods for defects and deformation in these optical detection methods. It causes the problems of complicated detection steps, inefficiency in engineering, and is not conducive to in-depth analysis of the detection results. This paper proposes a comprehensive defect and deformation measurement method based on dual-wavelength speckles, which is beneficial for solving the above problems. The measurement system includes four parts: the control module, the speckle binocular vision module for 3D morphology measurement, the speckle interferometry module for internal defect detection, and the data processing module. Firstly, the system should perform trinocular calibration. Then, the control module controls the speckle interferometry module and the speckle binocular vision module to emit lasers with different wavelengths. Speckles of different colors and sizes are formed on the surface of the composite material specimen. The cameras corresponding to the two modules are controlled to capture speckle images. The data processing module processes the speckle images separately to obtain defect and morphology information. It then uses the information fusion algorithm to integrate the 2D defect and 3D morphology information to complete the measurement. Composite material specimens with internal defects of different sizes and shapes were measured. Finally, the comprehensive detection of both internal defects and 3D morphology of composite materials was realized with this method.

Phase retrieval (PR) is widely applied in wavefront sensing for adaptive optics, diagnosing the aberrations, and wavefront measurement of optics elements. A single lens is often used in PR models to achieve better transmission of optical radiation thereby avoiding loss of high frequency information. In this paper, the sampling requirement of PR wavefront measurement model based on numerical Fourier optical theory is analyzed clearly. First, combined with the Fresnel diffraction theory, the diffraction field of the wavefront after passing through the lens is established. Next, according to the Nyquist sampling theorem, the sampling requirements for the phase factor of wavefront spatial frequency are deduced. Further, according to the relationship between the pixel size of CCD and the sampling pitch of pupil surface, the constraints and applicable range of PR model based on various diffraction transform are discussed quantitatively. The numerical simulations are carried out to verify the effectiveness of PR model based on the GS algorithm within the analyzed diffraction constraints, which shows that the recovery accuracy of the PR model can reach 0.0025 λ. The established sampling strategy and the constraint theory in this paper would provide a theoretical guidance for full-band wavefront measurement of the PR technology.

Grating encoder is a sinusoidal encoder based on grating diffraction principle, which is currently utilized in many high-precision displacement systems because of its advantageous characteristics: low cost, simple structure, works in harsh environments, high reliability, and so on. The output signal of grating encoder usually contains noise interference error, amplitude inconsistency error, DC bias error, harmonic error and quadrature phase error. These non-ideal factors are the main reasons for affecting the precision of subdivision.
In the traditional signal subdivision system, it is usually necessary to compensate each kind of error separately, which will consume many hardware and computing resources and cause a significant output latency, especially in the filtering section and normalization section. In this paper, a non-linear Kalman filter-based sin-cos wave subdivision method is proposed. Compared with the traditional filtering methods, non-linear Kalman filter has higher dynamic response and can provide instantaneous phasor estimation. In addition, it can simultaneously achieve filtering, amplitude normalization, decoupling DC bias, harmonic suppression, and phase compensation functions, which significantly reduces the computational burden and facilitates the implementation on low-cost processors.
In this study, a non-linear Kalman filter-based signal segmentation system is implemented on an FPGA platform and verified on a six-degree-of-freedom grating ruler platform. The results show that the single-channel output delay is only 1.8us at a 50MHz clock, which has a very high real-time ability. When the frequency and amplitude of the input signal varies, the non-linear Kalman filter can track instantaneously and has high dynamic characteristics. Experimental results show the effectiveness of this method.

The objects with complex scattering properties with rough surfaces and heterogeneous media are widely used in various light-guiding devices, car dashboards, luminaires, and other illuminating systems as elements of scenes aimed to generate images with photorealistic quality. In most cases, such properties are described with Bi-directional Scattering Distribution Functions (BSDF). Typically, such functions are obtained with different measuring devices, like goniophotometers. However, the measurements of such functions are a complex task because of their multidimensional character and complex angular shape. At the present a lot of devices aimed at BSDF measurements have been developed, however all of them have a set of drawbacks, for example, it may be very complex construction, which makes such devices expensive in the manufacturing, or noticeable overall dimensions, what results in their inconvenient not portable usage, low speed of measurements. On the other side, other simpler category of BSDF measuring devices does not have sufficient accuracy, a restricted number of measurement directions, and a very restricted set of functions not allowing to measure such complex optical effects as polarization and fluorescence. In the given paper an original construction of the BSDF measuring device is considered, which does not have the mentioned drawbacks and combines most of the advantages of existing solutions. The proposed measurement setup has small overall dimensions, a simple and cheap construction keeping high accuracy and measurement speed, and a wide set of supported effects like polarization and fluorescence. The advantages of the developed measurement setup are proved with the accurate computer model based on BSDF obtained with the measurements of real samples.

High power and high beam quality laser sources are required in numerous applications such as nonlinear frequency conversion, optical pumping of solid-state and fiber lasers, material processing, and others. Here, we theoretically study and demonstrate a tapered laser diode with integrated metalens, which can greatly reduce the lateral far-field divergence of the device. A 980 nm tapered laser diode adopted in this design consists of a power-amplified tapered section and a narrow-ridged section, in which the latter restricts the lateral mode number, and the former is utilized to amplify the output power. The wavefront is carefully reshaped by preparing a one-dimensional (1D) trench metalens near the front facet of the tapered cavity. By precisely designing the length and width of the low refractive index elements at different positions, the approximate spherical wave formed by diffraction in the tapered cavity is transformed into an output plane wave while ensuring high transmittance (>90%), which reduces the divergence of the lateral far-field. The simulation results show that the lateral far-field divergence of the fundamental mode decreases from 3.2° to 2.0° (FWHM) after the integration of the metalens with a 500 μm length of tapered cavity.

Quantum dots (QDs) exhibit exceptional optical qualities, including wide excitation wavelength, small full width at half maximum (FWHM), and photobleaching resistance. It had been used to make color-converting diffusers for backlight modules. In this study, the QDs were added into masterbatches to prepare composite components with the functions of diffusion and color conversion. Using a coextrusion approach, masterbatches were made by adding suitable ratio of red and green QDs as color conversion materials in polystyrene (PS), silicone difussion powder as the light diffusing agent, and adding antioxidants to improve the service life of the masterbatch. After that, the QD color masterbatch with uniform dispersion, controllable concentration and good luminescence performance was obtained. A spectrometer was used to examine the photoluminescence performance of the created masterbatches in order to validate their luminescence performance. As a result, the use of QDs masterbatches is a viable option for the application of high performance QD display device.

Using waveguide to propagate images from micro displays to human eyes can effectively reduce the size and weight of AR equipment. For the optical design, we need grating structures to couple rays into or out of waveguide with sufficient uniformity while remaining the most efficienct. Additionally, enlarging the FOV (Field of View) and taking chromatically into account are important for offering an immersive experience for AR users. From the CAE tools perspective, the critical challenge is to consider the requirements all together. Hence, the key for waveguided AR design is a feasible design flow and comprehensive simulation tools to address the design challenges. We successfully integrated wave optics phenomenon into geometrical optics results to complete a waveguide AR glasses optimizing design by using Synopsys RSoft RCWA tool DiffractMOD, LightTools and parametric BSDF interface.

This article explores the possibility of using multicriteria applied to the ray tracing result processing method to improve the efficiency of performing groups of repetitive calculations. If the usual ray tracing criterion is a filter that passes rays in accordance with some condition, usually a series of events that must happen to the ray by the time it reaches the radiation receiver, then multicriteria contains not one criterion, but a set of criteria, each of which is assigned to certain result of the calculation. The proposed concept of multicriteria was developed to solve the problems of scattered light analysis in optical imaging devices. Existing mechanisms make it possible to find sources of stray illumination of an image, but they only show the average value of stray illumination formed by an element of an optical device. In most cases, it is necessary to know the nature of the distribution of stray illumination in the image. Using the concept of multicriteria allows you to effectively solve this problem. Within the framework of one computational process, criteria are formed that correspond to the detected scattered light sources, and each of the criteria is associated with its own image. Using a special technique of ray tracing and processing of ray tracing results, separate results are generated for each of the criteria. This technique can be used not only for the analysis of scattered light, but also for modeling multichannel and multiconfiguration systems. The paper presents the results of scattered light simulation in two optical devices and virtual prototyping of the GP-200 goniophotometer.

Large DOF (depth-of-field) with high SNR (signal-noise-ratio) imaging plays an important role in many applications such as unmanned driving to medical imaging. However, there is always a trade-off between DOF and SNR in traditional optical design. In this paper, we propose a NIR&VISCAM (NIR&VIS Camera) that combines multi-spectral optical design and deep learning to realize large DOF and high SNR imaging. Specifically, a multi-spectral optical imaging system based on the HVS (human visual system) is designed to provide colorful but small DOF VIS (visible) image and large DOF NIR (near-infrared) image. To achieve DOF extension, we build a fusion network NIR&VISNet consisting of a VIS encoder for color extraction, a NIR encoder for spatial details extraction and a decoder for information fusion. We establish a prototype to capture real-scene dataset containing 1000 sets and test our method on a variety of test samples. The experimental results demonstrate that our NIR&VISCAM can effectively produce large DOF images with high quality. Moreover, compared to the classic image fusion methods, our designed algorithm achieves the optimal performance in DOF extension and color fidelity. With the prominent performance in large DOF and high SNR imaging, this novel and portable system is promising for vision applications such as smartphone photography, industry detection, and life medical.

To realize the fast and simple in-orbit aberration correction of TMA telescope, an aberration correction method based on Convolutional Neural Network (CNN) is proposed. CNN is trained to establish the relationship between the defocus point spread function and the misalignments of the secondary mirror. The wavefront aberration caused by the figure errors of the primary mirror and the misalignments of the secondary mirror and the tertiary mirror can be compensated by adjusting the secondary mirror according to the outputs of the well-trained CNN (named as Cor-Net). This method can correct the system aberration quickly and the RMS of the system wavefront aberration is reduced from about 1.5 λ to 0.1 λ by only three correction cycles.

The Sun Yat-Sen University (SYSU) 1.2-m Multi-Terminal Telescope is a versatile astronomical facility with three-channel photometric and low-/high-resolution spectrometric functions. The SYSU telescope comprises a Ritchey-Chretien Cassegrain bi-reflection system with a working waveband ranging from 300 to 1000 nm. Within the field-of-view (FOV) of 15′, the image quality represented in 80% encircled light energy is concentrated within 0.3 arcsec.

A Cassegrain instrument unit is mounted on a telescope derotator that enables working modes to be switched among four instruments by a central switching mirror. The equipped instruments include a three-channel photometric terminal, a 1.25-inch visual observation terminal, a wavelength calibration unit, a long-slit spectrograph (LSS), and a fiber adaptor for high-resolution observation. Therein, the photometric terminal can perform simultaneous imaging in the b(320-450 nm), g(480-700 nm), and r(730-1000 nm) bands. By adding a set of corrective lenses, the visual observation terminal can also realize a large FOV of 0.76°. The LSS can provide high-throughput observation, with the resolution ranging from 1000 to 3000 by slit width. A high-resolution spectrograph (HRS) at the laboratory is fed by a 25-m fiber from the Cassegrain fiber adaptor. The resolution R of the HRS exceeds 30,000 to cover a wide band from 400 to 900 nm. The SYSU 1.2-m Multi-Terminal Telescope combines excellent photometric and spectrometric observational performances. The novel design of the SYSU telescope allows for a singular telescope to make contributions in both astronomical education and scientific research.

A varifocal lens with a large focal length range is an indispensable optical part for applications such as biomedical engineering, intelligent robot, industrial image, and virtual-real. A key feature of Alvarez lenses is that the focal length can be tuned using small lateral rather than axial translation. Dielectric elastomer (DE) is a kind of ‘smart’ non-ionic electroactive polymer material. DE can be used as a soft actuator to produce the lateral translation for the Alvarez lens due to its reversibly large strains with a fast response speed, low cost, lightweight, and simple manufacturing process. When a driving voltage is applied to the compliant electrodes of the DE, an electrostatic force named Maxwell stress reduces the distance between the electrodes, thus the DE expands in the lateral directions. The focal length range of the Alvarez lens actuated by DE is not only determined by the parameters of the Alvarez lens but also by the parameters of the DE. To achieve large lateral displacement for achieving a large focal length range, three Alvarez lenses actuated by DE with different pre-stretched ratios and diameters are experimentally studied in this paper. Firstly, we develop and fabricate three Alvarez lenses actuated by DE with different pre-stretched ratios and diameters. Two Alvarez lenses, actuated by DE membranes with the same diameter of 38 mm, but with different pre-stretched ratios, i.e., 200% and 260%, respectively, are fabricated. In addition, an Alvarez lens actuated by DE membrane with a pre-stretched ratio of 260% and diameters of 30 mm is fabricated. Secondly, a driving voltage is applied to the DE membrane to actuate the Alvarez lenses. The driving voltage is generated using a function generator and the amplitude is amplified by a high-voltage converter. Lastly, the focal length ranges of the three Alvarez lenses are measured by the magnification method. A young embryo of the capsella bursa-pastoris section is selected as the imaging object and placed 2.0 mm from the fabricated Alvarez lenses. By measuring the object height in the captured image under different driving voltages using a microscope, the focal lengths of the three Alvarez lenses are obtained. The results show that the Alvarez lens actuated by a dielectric elastomer with a large pre-stretched ratio and diameter has a wider focal length range under the same driving voltage. The study is beneficial to designing and developing an Alvarez lens actuated by DE for optical imaging applications that require wide focal length tuning capacity.

In this paper, the lightweight design and analysis of the primary mirror structure for space camera with a diameter of Φ302 mm is carried out. The primary mirror material is glass ceramic and is fixed by peripheral support. It is necessary to minimize the weight of the primary mirror while meeting the complex mechanical conditions during launch and on-orbit. First, through comparative analysis of several lightweight forms, it is determined that the hexagonal honeycomb structure is selected as the final lightweight structural. Secondly, the finite element analysis and Zernike polynomial are used for iterative optimization. Under the condition that the RMS of the primary mirror surface shape accuracy needs to be better than 10 nm, the final result of the primary mirror mass of 5.46 kg and the light weight rate of 30% is obtained. Thirdly, in order to check the environmental adaptability of the primary mirror, statics and dynamics were analyzed. The analysis results show that the structural strength of the primary mirror can withstand 10 g overload acceleration and the first order mode is greater than 500 Hz. Finally, the optical mirror surface of the primary mirror is detected by the interferometer, and the surface shape accuracy RMS is 7.5 nm, which effectively proves the accuracy and reliability of the lightweight design and analysis of the primary mirror. This paper provides ideas and references for the lightweight design of small and medium-caliber mirror structures.

Infrared Search and Track (IRST) system has been widely applied to cover a wide field-of-view in surveillance systems to passively search, detect, track, classify several objects at as long ranges as possible. In order to achieve that wide area of coverage the optical system must have a relatively large field of view which ultimately limits the observation range due to the fixed size of detector and optical performance of the system. The IRST system could integrate with a Forward-Looking-Infrared (FLIR) camera with longer focal length which increases the observation distance in required situations; this solution would make the IRST system become unnecessarily complex with two separate optical cameras. This paper introduces a mid-wave infrared (MWIR) lens design which has both abilities of high-speed scanning and optical zooming for Infrared Search and Track (IRST) system. A reflecting mirror is integrated within the optical system to perform the scanning function by stabilizing light-of-sight of the optical axis. The scanning mirror is placed to be conjugated with an afocal telescope which has the function of optical magnification. In scanning mode, the field of view is 20° x 16° for a single frame at a maximum scanning angle of 4.32°. In optical zooming mode, the minimum field of view is 6.7° x 5.3° which makes the optical zoom power of 3X. All configurations of the optical system are designed to work with a F/2 SXGA (1280 x 1024) cooled detector having a pixel pitch of 15µm.

Wavefront-based aspheric metrology techniques generally require a compensation lens to compensate for the primary aberrations. To expand the adaptability of the surface to be tested, this paper proposes and demonstrates a partial null compensator structure that can switch between the front and back mirror sides. The presented compensator comprises two sets of off-axis reflecting parts and a pre-compensation spheric lens in an integrated structure. An appropriate off-axis reflection combination mode can be selected for the range of the conic coefficient of the measured surface. With the simulation result, the presented compensator can adapt to a large-scale variation of the surface conic coefficient K from -10 to +10. The average residual wavefront aberration is no more than 1λ (PV) and 1/4 λ (RMS). The results show that the proposed structure can be efficiently applied to wavefront detection or interferometer for data post-processing.

The combination of spectroscopic technology and machine learning algorithm for rapid identification of microplastics provides great technical support for the field detection of microplastics, which is a new field that has attracted great attention. Raman spectroscopy can identify organic and inorganic additives and coatings, as well as polymer substrates. However, under the action of fluorescence, additives or pigments affect the Raman spectrum signal. Infrared spectrum detection technology can usually for polymer gives a direct identification of information as a result, the problems existed in the Raman spectroscopy detection technology to evade, but if the detection technology for the additive, especially trace amounts of additives are hard to measure, so the Raman spectroscopy detection technology and infrared spectrum detection technology can complement each other. In this paper, Raman-infrared spectroscopy fusion detection technology is used to compare the combination of random forest (rf), Extreme Gradient Boosting (XGBoost, xgb), and Artificial Neural Network (ANN) three machine learning classification algorithms to build a high-speed and effective recognition and classification model of microplastics. Raman and infrared double-channel microplastic detection system was used to collect the spectral data of 13 common microplastic standard samples. In order to prevent over-fitting, each sample was sampled several times, and a total of 1430 microplastic samples were collected. The 2068 spectral data points of Raman spectral data were compressed to 512 and fused with infrared spectral data. The XGBoost algorithm was used to rank the importance of the fused data, and a total of 69 features which had a great influence on the recognition accuracy were extracted. To eliminate dimensionality, min-max normalization is used to linearly transform the original data, mapping the original data values to between [0-1]. Rf, ANN, and XGBoost algorithm were used to establish the microplastic recognition model for 69 data features extracted after dimensionality reduction, and the confusion matrix and 10-fold cross validation were used to evaluate the model. The results show that the recognition accuracy of single hidden layer ANN model is 97%, that of double hidden layer ANN model is 98%, that of XGBoost model is 97%, and that of random forest model is 99%. The overall performance of random forest model is better than XGBoost model and artificial neural network model.

The 5G fronthaul optical modules are the basic building block of the 5G network and WDM solutions are desired. Application code of MWDM has just been defined in ITU SG15 in December 2021 and are currently under intense study, naming draft recommendation G.owdm2. We organized the investigation and evaluation of MWDM optical modules from different vendors. Key parameters of optical/electrical interface have been tested and analyzed, including wavelength deviation, 20dB bandwidth, total mean output power, optical sensitivity, optical path penalty, eye diagram, power consumption as well as DDM function. Current commercial 25G MWDM optical modules are demonstrated capable to support transmission in O band covering almost all scenarios of 5G fronthaul.

Virtual reality (VR) and augmented reality (AR) have widespread applications in education, military, medical treatment, and entertainment. The key parameters of near-eye displays, such as field of view (FOV), eye box size, resolution, and virtual image distance will critically influence the performance of the final display products. Meanwhile, VR and AR displays are designed to achieve a very wide FOV to improve the immersive visual experience recently. Especially in VR applications, the FOV has been more than 90° to blur the boundary between the virtual and real world. Thus, a wide-angle forward-stop anthropomorphic vision lens for VR and AR inspection should be studied. However, it is very challenging to achieve wide FOV and high resolution simultaneously in a compact pinhole lens. In this study, a pinhole lens using an advanced photo system-classic (APS-C) size sensor with a FOV of 110° and an entrance pupil diameter (EPD) of 4 mm is designed. The optimization process is introduced, and the optical performance is analyzed. In our design, optical aberration is well corrected to improve the image quality. The cut-off spatial frequency of the modulation transfer function (MTF) across the whole field is 200 cycles/mm. The MTF is greater than 0.43 at the Nyquist frequency (NF), the field curvature is controlled within 0.04 mm, and the distortion of the system is less than 10% across the 0.82 field. The overall length (OAL) of the system is less than 230 mm. The result shows that our pinhole lens is a high-resolution wide-angle optical system and meets the requirements for VR and AR inspection.

EEG signals classification plays a crucial role in motor imagery brain computer interface systems. Traditional convolutional neural networks tend to ignore temporal information when classifying motor imagery EEG signals, it uses a single-scale convolutional kernel, resulting in poor classification performance. In this paper, we propose a parallel fusion algorithm based on dual attentional multi-scale convolutional neural networks (DAMSCN) and long and short-term memory (LSTM). Firstly, DAMSCN uses convolutional kernels of different sizes at the same layer to extract time-frequency features of EEG signals at different scales, and introduces a dual attention mechanism. At the same time, LSTM extracts temporal features from the EEG signals. Then, the fusion and classification of all features is achieved with the help of fully connected layers and softmax layers. Finally, experiments are conducted on domain-specific public dataset to verify the performance of the algorithm.

With the advancement of aerospace technology, space debris generated by the collision and shedding of failed spacecraft is increasing, which threatens the safe operation of spacecraft in orbit seriously, and arouses people's attention to the detection of space debris. To achieve high-performance detection in dark environments, we propose a large relative aperture space-based detection optical system, which has a field of view of 16°, focal length of 182mm, F number of 1.52, and a working wavelength of 450~850nm. The system contains total 11 lenses, making the imaging performance more sensitive to temperature, therefore, we carry out thermal analysis for the system and use optical compensation method to achieve athermalized design. Finally, the system can work in the range of -10°C~+30°C, and the variation of the radius of the spot diagram with temperature is less than 3μm. In addition, we control the influence of stray light in the design process in order to observe bright and dark targets simultaneously. The numerical simulation results demonstrate that the veiling glare index of the system is 2.9%, which meets the requirement of dark object observation. The proposed optical system with large relative aperture and excellent imaging quality could be applied to accurate detection of space debris.

This work proposes a research scheme to speed up the design of metasurface skin cloak through low-complexity phase monitoring model and deep learning. This skin cloak conceals a three-dimensional arbitrarily shaped object by complete restoration of the phase of the reflected light at specific wavelength. And the possibility of realizing spectral prediction by deep learning is analyzed. During the study, a phase monitoring system was designed in which the detector, the light source and the monitored nano-antenna were sequentially distributed at equal distances from the emitted wavelength of the light source, so that the monitored phase amount was exactly equal to the phase change before the reflected wave, thus eliminating the need for multiple monitors to measure and calculate the phase change before and after the reflection. The traditional metasurface design is usually constructed by manual library construction based on the phase distribution and the relationship between phase variation and dimensional variation of the cell structure, so this work combines the aforementioned monitoring model with deep learning to generate the database required for modeling. The two variable parameters of device length and width were first defined, and the reflected wavefront phase change used as the optical response, and we reprocessed the original data and finally build and trained an artificial neural network model for forward prediction of optical response. This network can obtain its MSE below 0.001 for the test set after the training is completed. Thus the scheme can replace the role of simulation software to some extent, and its prediction process can be completed in a few milliseconds, improving the efficiency of the design metasurface process.

The star sensor is an attitude-sensitive device for spaceflight. It is a critical component in the autonomous attitude determination of aerospace vehicles. Compared to other attitude sensors, the star sensor offers higher attitude accuracy, low power consumption, small volume, and strong autonomy. It plays an important role in high-precision remote sensing, astronomical navigation, and other fields. Star extraction is an essential part of the star sensor in the process of working. Its accuracy and the number of extracted stars affect the performance of the star sensor. This paper proposes a method of star extraction based on the combination of the Improved Optical Flow Method (IOFM) and Dynamic Filtering (DF) named IOFM-DF. Based on the optical flow method, the motion characteristics of stars in the time and space domains are considered. Due to the difference between the star and noise in the motion trajectory, dynamic filtering is used to reduce the influence of noise from the star image on the extraction effect of the star. Considering the statistical properties of the motion trajectories of multiple stars, the cosine distance of the motion track between the extracted point and the star is calculated to predict the probability that the extracted point belongs to the star. IOFM-DF can extract and track stars in the star image for a low signal-to-noise ratio. Experimental results show that IOFM-DF increases the number of star extractions by at least 30% compared to traditional methods. This research is important to improve the accuracy and performance of star sensors.

Infrared imaging system is widely used in unmanned aerial vehicle (UAV) detection because of the advantage of precise monitoring and anti-interference. However, it is difficult to simultaneously achieve large field of view (FOV) and light weight. In this paper, we propose a compact infrared panoramic annular lens (PAL) system with a large FOV and a three-piece simple structure, which contains three standard spherical lenses and has a FOV of (30°~100°) ×360°, total length of 51.6 mm, maximum diameter of 72 mm, focal length of 2.2 mm, and F number of three. The modulation transfer function of the system is higher than 0.7 at the Nyquist frequency, and F-theta distortion is controlled to less than 2%, which can meet the requirements of UAV detection. In addition, we use optical compensation method to achieve athermalized design in the range of -40°C~+80°C. The system possesses low sensitivity in tolerance, therefore we design a straight-tube mechanical structure for the system to simplify the assembly process and ensure the assembly precision at the same time. The PAL system we proposed is easy to be carried by UAVs due to its features of large FOV and lightweight, which can achieve accurate detection, large-scale monitoring, target recognition and tracking in harsh environments. It has important application value in military, security monitoring, machine vision and other fields.

In practical application scenarios, the behavior of users watching movies is random and diverse, and also includes spatiotemporal features. Aiming at the fact that the complex ranking model cannot use a large amount of data for learning and updating in real time, especially the problem of insufficient training data for inactive users, this paper proposes a pre-training-based user embedding algorithm model. In the pre-training stage, the SINE model is used to dig out several intents with the highest user interest, improve the hit rate of user interest, and thus improve the accuracy of Inference. The follow-up test results show that the newly constructed recommendation model has better performance, and the evaluation index AUC is increased by 2.4% compared with the model without pre-training, which proves the effectiveness and feasibility of the new algorithm.

Focal length is an important parameter to evaluate the performance of the varifocal liquid lens. To study the effect of the pre-stretched ratio of the dielectric elastomer on the focal length, two varifocal liquid lenses driven by dielectric elastomer with different pre-stretched ratios (250% and 300%) are developed in this paper. When an actuation voltage is applied to the compliant electrodes of the dielectric elastomer, the surface curvature of the droplet alters, thus changing the focal length of the varifocal liquid lens. The focal lengths of the two varifocal liquid lenses are measured by the magnification method. The results show that the varifocal liquid lens with a smaller pre-stretched ratio has a larger focal length when the actuation voltage is lower than 3.0 kV. When the actuation voltage is larger than 3.0 kV, the varifocal liquid lens with a larger pre-stretched ratio has a larger focal length. The effect of the diameter of the DE on the focal length of the varifocal lens is also studied. The results also indicate that the varifocal liquid lens actuated by DE with a smaller diameter has a larger focal length when the actuation voltage is lower than 3.0 kV. When the actuation voltage is larger than 3.0 kV, the varifocal liquid lens actuated by DE with a larger diameter has a larger focal length. The study is beneficial to the development of a varifocal liquid lens with a wide focal length range.

The off-axis four mirrors telescope has the advantages of high image quality, high resolution and high integration, which makes it a core opti-mechanical component to adapt to the future development of multiband co-aperture airborne observation and aiming systems. The simulation and suppression of external stray light in the telescope is imperative for the airborne application since this type of systems is easily affected by strong light outside the field of view. For the asymmetry of the telescope, point source transmittance (PST) as a two-dimensional function varying with the horizontal and vertical angle of stray light was set up to evaluate the influence of external stray light. Besides, the conversion relationship between the horizontal and vertical angle and the process quantity of rotations about local coordinate axis required for opto-mechanical modeling was established. Based on that, stray light simulation model of an off-axis four mirrors telescope was constructed, then PST distribution of stray lights with different spatial angles in the whole incident hemisphere space was calculated. Furthermore, the imaging effect of long-distance scene under the influence of several stray lights with large PST peak was simulated, showing that the stray lights had great interference to airborne observation. According to the found transmission paths, the internal baffles were designed to significantly reduce the peak value of PST to reach the application indices. From the re-simulation results of the imaging effect of scene, the interference of residual stray lights was finally not obvious, which could meet the use requirements of airborne photoelectric observation and aiming system.

In order to simplify the structure of the centering system and measure the center deviation of the upper and lower surfaces of the optical lens group synchronously, a center deviation measurement system without moving parts based on liquid lens is proposed. The system adopts the reflection defocus measurement method and the bidirectional centering principle, the principle of system measurement is given, and the calculation formulas of tilt and decenter errors are derived. The results show that the system can achieve 0.5μm tilt measurement resolution and 2" decenter measurement resolution. Finally, the working logic and structure design of the system are given. The system has the advantages of simple structure, convenient measurement and high efficiency, and can measure the center deviation of the lens group without changing the measuring lens. It has a broad development prospect in the field of high precision automatic lens group assembly.

In this paper, a simple and effective method is proposed for measuring the focal length of a weak negative thermallyinduced lens. Generally, it is very difficult to measure the focal length larger than 1000 mm of a weak thermally-induced lens by utilizing the traditional procedures. In our experiment, we planned to construct a Yb:KGW laser system almost without the thermally-induced lens in which the focal length of the laser crystal should be measured precisely. With respect to the optical features of Yb:KGW crystal, the thermally-induced characteristics look like something of a negative lens with weak effects. The steps of measuring the focal length of a thermally-induced lens of the laser medium have been adopted as follows. First, the relationship between the focal length f1 of a positive assistant lens as well as the position of the assistant lens and the focal length fT of a thermally-induced lens were carefully analyzed and the experimental setup were designed through the theoretical simulation. Secondly, the variation of the spot size and post position for a He-Ne probe laser have been experimentally investigated after the probe laser beam passed through a thermally-induced lens (fT) and an assistant lens (f1) with the different drive currents of a pump LD with the wavelength of 980 nm. Then, the post position for a He-Ne laser beam can be obtained by use of a least square method, and then the focal length of a weak thermally-induced lens can be deduced with an indirect detection method. In this paper, we introduce a new technique for the measurement of the focal length with the absolute value large than 1000 mm of a negative lens, which has not been reported until now. The results might be useful for the evaluation of a weak thermally-induced lens of almost all solid-state lasers (SSLs).

Usually, a polynomial expansion of the deviation from a conic equation was used for describing a rotationally symmetric aspheric surface, which is also the data basis for the technology formulating of subsequent fabricating and testing. The degree of the surface asphericity is mathematically determined. But the parameters of the expansion provide little information about the aspheric shape measurement, even small differences of which can result in dramatic differences of the difficulty of fabricating and testing. For the process of aspheric surface designing, fabricating and testing in an optical system are separately. The testing method originates from the aspheric surface geometry, but the shape testing result can’t be fed back to the optical design. Based on the principle of detection-oriented, a new type of aspheric surface is proposed and characterized by the optical path parameters of its partial null testing. When a new aspheric surface was optimized in the design of an optical system, the measurement optical path of the surface was achieved at the meanwhile. A three-band fusion imaging system is designed with two mirrors of the partial null aspheric surface type. The results show that the imaging quality can meet the resolution of detectors in each band. The PV values of emergent wavefronts of the partial null detection optical paths for each mirror are about 7λ and 12λ, respectively, and the distributions of which are uniform and detectable.

Ultraviolet astronomical observations are significant for studying the early-type stars including O, B, A-type stars, white dwarfs, and central stars of planetary nebulae, which could have the strongest radiation in the ultraviolet region. Since ultraviolet astronomical observations are mainly carried out in space, this paper proposed several compact, light-weight and large-field ultraviolet astronomical optical systems for space observations, including refractive optical systems, catadioptric optical systems, off-axis three-mirror systems, and coaxial four-mirror systems. Combined with the optical designs, we discussed the characteristics of the designed systems, and the possibility for infrared observation by all reflective optics. In the paper, we introduced four compact optical designs: the 100 mm aperture F/2.5 refractive system with 12-degree field of view, the 100 mm aperture F/2.5 catadioptric system with 10-degree field of view, the 100 mm aperture F/3 off-axis three-mirror system with 10-degree field of view, the 100 mm aperture F/2 coaxial four-mirror system with 6-degree field of view. Optical performances and space adaptability of these designed telescopes are analyzed and compared in this paper.

A f-theta laser scanning optical system with wide scanning angle, high resolution and compactness is proposed. Specifications of the system are analyzed and calculated. To simplify the optical layout and improve the optical performance, freeform surfaces are used to describe the shape of the lens. The method about how to create a user-defined surface in the optical design software is introduced. The optimization strategy and implementation method of freeform surface are mentioned. The design result achieves a f-theta laser scanning optical system with a field-of-view of ±55.6°, a resolution higher than 600 dots per inch, and a total length less than 150mm. The modulation transfer function of the system is close to the diffraction limit and the linear distortion is less than 3μm.

Aiming at the problems of traditional wavefront coding system, such as single phase mask (modulation) and limited extended depth of field, a wavefront coding imaging system using deformable mirror (DM) is proposed to realize dynamic coding. In this paper, continuous pure phase coding based on Zernike polynomial is designed by the simulated annealing algorithm for different defocus distances, with the aim of thus getting the most suitable coding strength for different defocus distance. And in the decoding process, the PSF of the defocused position corresponding to the blurred image is used for restoration, which reduces the artifacts caused by using the PSF of the focal position to restore all the defocused images. The experiment shows that compared with the traditional fixed phase mask, the wavefront coding imaging system of DM can achieve dynamic coding and decoding, which increases the imaging flexibility of the wavefront coding system and improves the quality of the decoded image.

For the demand of line chromatic confocal displacement measurement, a new multi-channel compact spectrometer needs to be developed. In this paper, a microlens array-grating structure, in which one side is microlens array and the other side is blazed gating, is proposed for a miniature spectrometer. The microlens array-grating structure can be pressed in the form of "sandwich" by soft lithography using PDMS material. The micro lens array is a 10*10 mm square, consisting of 45*45 microlens elements, each with a diameter of 220 μm, and the outer diameters of the elements are closely connected with each other. The blazed grating is an equal period grating with a grating line density of 600 lines /mm and a blazed angle of 8°37’. By optimizing the design parameters, the image resolution of the spectrometer based on the grating-microlens array is within 1 nm in the wide band of 400 nm~700 nm. Different microlens grating surface elements have performance consistency with a standard deviation of about 0.5 nm, which can realize the function of arrayed micro-spectrometer.

By analyzing their polarization scattering characteristics, the concentration and species of suspended aerosol particles can be monitored and identified. The calibration of polarization measurement system cannot only ensure the measurement accuracy, but also help to establish characteristic polarization spectrum of particle species, and then classify and identify aerosol types. The particle monitoring technique in this paper is Stokes analysis combined with multi-angle scattering measurement method, which contains various error sources of airflow, optical and circuit. We propose a calibration method using ECM (Eigenvalue Calibration Method). The experimental process is divided into two processes: static calibration and dynamic calibration. Static calibration is to calibrate the error of traditional polarization optical system, and the measured error of Stokes vector in this work can be controlled within 0.03. However, for suspended particles flowing through light detection area with airflow, we need a further dynamic calibration to improve the measurement accuracy. Here we use polystyrene spheres with different particle sizes as standard samples. The experimental results show the feasibility of ECM method applied in such online optical analysis for suspended particles.

Electrochromic devices are widely used in smart windows, goggles, and anti-glare mirrors, exhibiting higher demand for color variety, especially in smart clothing, aerospace, and multi-color displays. However, current electrochromic materials ordinarily have a single-color modulation, which switches between two or three states. The application of multilayer metal-dielectric structured films as electrodes for electrochromic devices provides a wide variety of colors due to the superimposition of structural and electrochromic colors. This interference structure shows various stable structural colors, and no noticeable color change is observed in the angular range from 0° to 45°. Furthermore, the color starts to change asymmetrically when viewed from both sides due to the introduction of the metal layer. It can be observed that the front of the constructed electrochromic device is blue-green, and the back is purple when 3.5 V is applied. Therefore, the colors of electrochromic devices depend on the color-changing material itself and provide a wider color range through the design of the metal-dielectric structure, which creates a new direction in the aesthetic design of multi-color electrochromic devices.

In this study, a robust orbital angular momentum (OAM) beams-based Fizeau interferometer is proposed and experimentally demonstrated. It takes full advantages of the Fizeau interferometer and OAM beams, where two conjugated OAM beams propagate in a common optical path. Compared with the conventional dual-path interferometers, Fizeau interferometer has a simpler structure and higher stability, for its common optical path structure is less sensitive to the effects of the external perturbations. As a result, petal-like interference patterns can be stably observed on a CCD. By measuring the rotation angle of the petal-like pattern, tiny displacements ranging from 50 to 800 nm were stably and precisely measured with resolution of 40 pm in simulation and 750 pm in experiment. The proposed system may develop a more compact and stable scheme for the precision measurement in the future.

High frame rate of a spectrometer is very important for studying rapidly changing transient phenomena. Dispersive time stretch can map spectral information in the time domain for measurement and thus have a high frame rate compared to conventional spectrometers. To measure the emission spectrum and obtain higher sensitivity, a converging time lens was introduced. The spectro-temporal analyzer realizes the Fourier transform of the incident light field at the focal dispersion position of the time lens, maps the spectral information of the signal to be measured to the time domain, and also realizes the real-time acquisition of the signal spectrum. To further improve the resolution for higher precision detection, a larger pump pulse bandwidth was used to obtain a larger time lens window. Meanwhile, the optical frequency comb with slightly different repetition frequencies is used to sample the focused signal based on four-wave mixing to reduce the sampling bandwidth requirement. On this basis, a parametric time-domain spectrometer based on asynchronous optical sampling was proposed, and the third-order dispersion of the system is compensated. After these operations, the spectral resolution was increased from 20 to 1 pm with a detection bandwidth of 24 nm and a frame rate of 1 kHz. Finally, the random lasing spectral dynamics of EDFA and the thermal drift of the resonance peak of a microring resonator were detected.

The sources of different spurious radiation in infrared optical system are analyzed, and the measures to suppress the spurious radiation are listed. Taking the infrared optical system of a detector as an example, the stray radiation of the infrared optical system is suppressed by setting the lyot stop. The optical and mechanical structure model of the infrared optical system was established, and the Monte Carlo method in LightTools software was used for ray tracing analysis. The illuminance of the image plane of the detector after adding lyot stop was obtained, and the point source transmittance (PST) and veiling glare index (V) of the infrared system were calculated, and the effectiveness of the suppression effect was evaluated. At the same time, the background heat radiation of the internal optical and mechanical structure of the infrared optical system is simulated and analyzed. The comprehensive consideration ensures that the imaging quality of the infrared optical system is not affected.

In order to improve the robustness of the traditional laser tracking interferometry method and make the calibration results of the one-dimensional standard more accurate and reliable, a laser tracking interferometry calibration optimization method in multiple attitudes is proposed in this paper. The method firstly constructs a multi-stance 1D standard layout based on the traditional laser tracking interferometric length measurement, and collects measurement information under different attitudes by laser tracker, then uses a weight-based calibration result optimization strategy to optimize the combination of measurement data, and then outputs the calibration results and performs error source analysis and uncertainty assessment. The experimental analysis was carried out and compared with the CMM method, and the E_n value was 0.1, which verified the reasonableness of the uncertainty assessment, and the comparison with the measurement results of the CMM method showed that the calibration optimization scheme for multiple poses was more reliable than that for single poses. The optimized method provides a new calibration scheme for realizing the quantity traceability of high-precision one-dimensional standard, which has good practicality and certain guiding significance.

To improve environmental adaptability, an optical system with passive optical athermalization was designed. This system adopts a transmission structure with a spectral range of 0.4-1.0μm, a focal length of 166mm, a F number of 3.7 and a field view of 5°. An optical system with passive optical athermalization should satisfy three constraints. The first is the power distribution of each lens. The second is the achromatic equation. The last one is the athermal equation. A reasonable optical material combination is obtained by solving the three conditional equations. Then the initial optical system is simulated and optimized by Zemax. In the end, this system gains good imaging quality in the working temperature range of 10-30°C.

Interferometry is commonly used for an optical element surface accurate test. But the testing dynamic range is affected by the ambiguity of 2π. To solve this problem, dual-wavelength interferometry testing method has been proposed. The current dual-wavelength interference system usually uses two different wavelength monochromatic lights to work time-sharing and obtain their interference patterns respectively, which makes the system complex and measurement time-consuming. In this paper, we put forward a dual-wavelength testing method based on Michelson interference system. It enables simple and efficient extraction of the phase distribution of the tested optical element surface to be realized in a sub-millimeter scale dynamic range with a nanometer accuracy. A sodium lamp has two different wavelengths, 589 nm and 589.6 nm, it is selected as the light of our interference measurement system, so the equivalent wavelength is 0.579 mm. A dispersion element is adopted to make the interference patterns which correspond to 589 nm and 589.6 nm can be separated. Furthermore, in order to eliminate the influence of background light intensity on the interference patterns processing, we do Fourier transform for the patterns recorded by CCD to extract the spectral component related to the tested phase. And then, an inverse Fourier transform for this component is done to obtain the phase distribution. Finally, the tested optical element surface can be obtained from the phase distribution. Simulations have been done to validate the feasibility of the method. The test error of the surface profile is 0.252 nmRMS. The simulations prove that this method can guarantee high accuracy and expand the detection range.

Astronomical observation requires more distant and fainter object with a better resolution, so that the larger primary mirror telescope is needed to ensure the better resolution and light energy collection. However, the diameter of monolithic primary mirror is limited due to the manufacturing and logistics limitations. The segmented primary mirror is taken as an alternative solution to break the limitation. The segmented primary mirror must be co-phased to accomplish a diffraction-limited imaging. In this paper, we put forward a new method to measure the tip/tilt errors between the segments in whole aperture simultaneously based on analyzing the intensity distribution and Fourier optics principle. We set a mask with sparse multi-sub-pupils configuration on the segments′ conjugate plane. A point source is taken as the object of the segmented telescope, the pattern focused on the CCD is recorded as the point spread function (PSF). Then, the Fourier transform is performed for the PSF and we can obtain the optical transfer function (OTF) which is composed of the modulation and phase transfer functions (MTF and PTF). Tip/tilt errors can be extracted from the PTF side-lobes. Simulation and preliminary experiments have been done to validate the feasibility of the method. The accuracy of the method is 6.344x^10-16λ(λ=632.8nm) RMS when the tip/tilt error is less than 0.4λ, and when the tip/tilt error is in the range of [0.4λ, 2.4λ], the accuracy is 8.5x10^-15λ RMS. We also analyze the disturbance factor of the method in the simulation, including the piston error, the noise of the signal processing system, the surface shape error of the segments, etc. Furthermore, a preliminary experiment is built up to verify the three segmented system. This method has a higher detection efficiency and a lower hardware requirement which only needs a mask with sparse sub-aperture configuration.

The paper presents an algorithm for automatic synthesis of two-lens and three-lens objectives based on: the third-order aberration theory, selection of lens materials and ranking criteria of calculated systems. An original ranking system of calculated objectives is proposed by criterion of the axial point image quality and by criterion of the sensitivity to manufacturing errors of design parameters. Based on the developed algorithm, a program for automatic synthesis and ranking of two-lens and three-lens objectives was developed. The program helps an optical engineer to significantly simplify and accelerate the synthesis process of two-lens and three-lens objectives with the required image quality characteristics.