2023

• Record 337 of
  
  Title:Accurate dynamic quantitative phase imaging using multi-wavelength multiplexing
  
  Author(s):Fan, Chen(1); Li, Junxiang(1); Du, Yijun(1); Hu, Zirui(1); Chen, Huan(1); Zhang, Gaopeng(2); Zhang, Lu(1); Zhao, Zixin(1); Zhao, Hong(1)
  Source: Optics and Lasers in Engineering  Volume: 170  Issue: null  Article Number: 107757  DOI: 10.1016/j.optlaseng.2023.107757  Published: November 2023  
  Abstract:We present a novel, accurate, full-filed, dynamic quantitative phase imaging (QPI) technique by using multi-wavelength multiplexing and multi-plane iterative phase retrieval algorithm. In our method, a liquid crystal spatial light modulator is employed to flexibly generate multiple defocus intensity images at once, using its adjustable phase modulation characteristics of different wavelengths. Then these images contained at different wavelengths are captured by two color cameras with single exposure. To achieve accurate QPI, a multi-plane iterative phase reconstruction algorithm is also proposed based on transport of intensity equation (TIE). Finally, with these multiple defocus images, an accurate dynamic phase result can be provided by our approach. In addition, the errors caused by color coupling of color camera and chromatic aberration of the optical system are both analyzed and effectively compensated. Experiments conducted on the phase plate, living human colorectal cancer cells and human red blood cells well demonstrate the accuracy, dynamic measurement ability and flexibility of our method. © 2023 Elsevier Ltd
  Accession Number: 20233114459430
• Record 338 of
  
  Title:Combination algorithms applied to source reconstruction for neutron coded images and restoration for incomplete coded images
  
  Author(s):Li, Qiukai(1,2); Yan, Yadong(1); Wang, Feng(2); He, Junhua(1)
  Source: Review of Scientific Instruments  Volume: 94  Issue: 5  Article Number: 053301  DOI: 10.1063/5.0138742  Published: May 1, 2023  
  Abstract:The neutron emission of compressed capsules filled with fuels in inertial confinement fusion implosions can be measured by neutron imaging systems. Source reconstruction is an important method in coded-aperture imaging. In this paper, we use a combination algorithm to reconstruct the neutron source image. This method can improve the resolution and signal-noise ratio of the reconstructed image. In addition, the ray tracing method is used to obtain the point spread functions of the whole field of view (250 μm), and thus, the system response can be obtained. The edge gray interpolation method is used to restore the missing portion of incomplete coded images. The method can maintain a good performance when the missing-data angle is limited to less than 50°. © 2023 Author(s).
  Accession Number: 20232114115565
• Record 339 of
  
  Title:Co-phase error detection for segmented mirrors with ptychography
  
  Author(s):Li, Liangliang(1,2); Pan, An(1,2); Li, Chuang(1,2); Zhao, Hui(1,2)
  Source: Optics Communications  Volume: 537  Issue: null  Article Number: 129393  DOI: 10.1016/j.optcom.2023.129393  Published: June 15, 2023  
  Abstract:Co-phase error detection has been extensively studied as a key technology to achieve diffraction-limited imaging for telescopes with segmented primary mirrors. This paper provides a novel method to simultaneously detect piston, tip–tilt, and decenter errors of sub-mirrors based on an extended ptychographic iterative engine (ePIE). The main components of the detection system are a transmissive specimen and a detector near the focal plane of the segmented system. The specimen is mechanically moved across the stationary beam from the telescope with adjacent positions sufficiently overlapped, and the detector then records the diffraction patterns. After retrieving the wavefront aberration of the segmented primary mirror using ePIE, the decenter errors can be calculated based on the displacement of the pupil centers of sub-mirrors and the piston and tip–tilt errors can be computed by the least square method According to a series of numerical simulations, the root mean square errors (RMSEs) of the residual co-phase errors are below 0.01 λ. The results of preliminary experiments show that the relative errors of piston error detection and decenter error detection are 1.20% and 2.08%, respectively, which validates the effectiveness of our proposed method. © 2023 Elsevier B.V.
  Accession Number: 20231213748668
• Record 340 of
  
  Title:Thermal Insulation Structure Design and Simulation Analysis of Optical Measuring Device under Extremely Low-Temperature Based on Phase Change Temperature Control
  
  Author(s):Guo, Hailong(1,2); Zhang, Zhi(1)
  Source: Journal of Physics: Conference Series  Volume: 2492  Issue: 1  Article Number: 012002  DOI: 10.1088/1742-6596/2492/1/012002  Published: 2023  
  Abstract:To meet the thermal insulation requirements of the measurement system in the liquid oxygen tank of the rocket, we designed the thermal insulation structure of the optical measuring device at an extremely low temperature based on phase change temperature control, selected neicosane as the phase change material, and used 15 mm phase change layer to combine with 9 mm polyurethane thermal insulation layer to achieve passive temperature control. Finally, a thermal simulation model is established for transient thermal analysis. The simulation results show that the internal temperature of the system decreases from the initial temperature of 50 °C to -13.9 °C after 2 hours, which proves that the design meets the requirements. © Published under licence by IOP Publishing Ltd.
  Accession Number: 20232214160679
• Record 341 of
  
  Title:Terahertz fiber with multi-concentric ring cores for OAM modes propagation
  
  Author(s):Yuan, Yuan(1); Kong, Depeng(1); Guan, Lei(1,2); Wang, Lili(1); Li, Wenlong(1)
  Source: Physica Scripta  Volume: 98  Issue: 4  Article Number: 045504  DOI: 10.1088/1402-4896/acbf87  Published: April 1, 2023  
  Abstract:A novel fiber incorporating central hollow, porous isolated layers, and concentric ring cores is proposed for the simultaneous propagation of multi-terahertz (THz) orbital angular momentum (OAM) modes with low-level inter-core and inter-mode crosstalk. The designed fiber can efficiently support 132 OAM modes in 0.6 ∼ 1.5 THz, 178 OAM modes in 0.7 ∼ 1.5 THz, etc, the high-order radial modes are suppressed within the whole frequency range meanwhile, and the number of OAM modes can be further boosted by further increasing the number of ring cores. In addition, the fiber has low confinement loss, flat dispersion, and high purity over a wide operating range. Hence it can be applied in mode-division multiplexing (MDM) based on OAM combined with core-division multiplexing (CDM) in THz range, and is also compatible with wavelength-division multiplexing (WDM) and multi-level modulation formats. The realized fiber is expected to dramatically extend the transmission capacity and spectral efficiency. © 2023 IOP Publishing Ltd.
  Accession Number: 20231213774330
• Record 342 of
  
  Title:Research Progress of Raman Spectroscopy Technology for Deep Space Exploration
  
  Author(s):Zhao, Yiyi(1,2); Xue, Bin(1,2); Huang, Shuaidong(1,2); Xie, Xinmei(1,2); Yang, Jianfeng(1,2)
  Source: Guangxue Xuebao/Acta Optica Sinica  Volume: 43  Issue: 8  Article Number: 0822006  DOI: 10.3788/AOS221968  Published: April 2023  
  Abstract:Significance The detection of material composition on the surface of celestial bodies has always been an important content in lunar and deep space exploration. At present, the main detection means of material composition on the surface of celestial bodies is visible-near-infrared spectroscopy. Given the wide variety of material components on the surface of celestial bodies, attention should be paid to their chemical properties and content. The current single payload is difficult to meet these requirements, and it is necessary to develop new scientific payload technologies. Over the past two decades, the potential of Raman spectroscopy as a tool for lunar and deep space exploration has been intensively explored. Raman spectroscopy has the advantages of no need to prepare samples, fast and non-destructive analysis, and clear identification of molecular information. Thus, it is very suitable for the in situ detection of celestial bodies. Compared with visible and near-infrared spectroscopy, Raman spectroscopy has unique advantages in the detection of celestial surface materials. 1) The Raman spectrum peaks are clear and sharp without overlapping, which is conducive to the identification of minerals, especially for the composition and content measurement of mixed minerals. 2) It is not only easy to identify feldspar minerals, but also can detect other iron-free minerals. 3) It can detect inorganic substances, hydrous minerals, and organic substances at the same time. Therefore, Raman spectroscopy is a method with important application value and potential for the detection of material composition on the surface of celestial bodies, which complements the advantages of traditional visible light and near-infrared spectroscopy. Progress Since the first commercial laser Raman spectrometer came out in 1987, Raman spectroscopy, as a powerful spectral analysis technique, has been widely applied in various material analysis fields. In 1995, Wang et al. first proposed the application of Raman spectroscopy on the lunar surface to detect its surface material composition. Subsequently, scientists successively proposed to apply Raman spectroscopy technology to the detection of extraterrestrial celestial bodies such as the moon and Mars and put forward optical probe type short-range detection Raman, long-range Raman, and time-resolved Raman. Raman spectrometers served as a potential payload in the Mars Exploration Rover mission of American and Tianwen-1 mission of China but ultimately were not adopted due to low technology maturity. With the development of lasers, charge-coupled devices, and other instrument components, the application of Raman spectroscopy technology to deep space exploration has become a reality. After years of verification of principle devices, various countries have added or plan to add Raman spectrometers to the payload queue for deep space exploration. The Perseverance Mars rover launched by NASA in 2020 is equipped with two Raman spectrometers SHERLOC and SuperCam. SHERLOC mounted on the robotic arm is a close-working deep-UV Raman and fluorescence spectrometer. The SuperCam is mounted on the mast and includes an image intensifier-based long-range time-resolved Raman spectrometer with a working distance of 7-12 m. ESA's Mars rover ExoMars is preparing to carry a Raman spectrometer RLS. RLS mounted inside the cabin is a close-range Raman spectrometer with an excitation wavelength of 532 nm. Japan's Phobos mission MMX is also preparing to carry the Raman spectrometer RAX. RAX mounted at the bottom of the rover is a close-range Raman spectrometer with an excitation wavelength of 532 nm. China's Chang'e-7 lunar exploration mission also plans a Raman spectrometer. The Chang'e-7 Raman spectrometer is a long-range time-resolved Raman spectrometer based on an image intensifier, with an excitation wavelength of 532 nm and a working distance of 1. 2-3. 0 m. Table 1 lists the parameter comparison of the above five Raman spectrometer payloads. This paper analyzes and discusses the key issues of Raman spectroscopy for deep space exploration. Due to the laser ablation limit of the material, there is a contradiction between the signal intensity of Raman spectroscopy and its spatial resolution. Long-range Raman spectrometers should focus more on signal strength, while close-range Raman spectrometers should focus more on spatial resolution. In terms of excitation wavelength selection, each excitation wavelength has its advantages and disadvantages. The most important thing in the selection of excitation wavelength is to consider the priorities of various scientific mission objectives. Fluorescence suppression is still one of the main problems faced by Raman spectroscopy. Infrared/ultraviolet excitation, time gating, frequency-shift excitation, and photobleaching are effective methods for suppressing fluorescence in deep-space Raman spectrometers. Raman spectroscopy technology for deep space exploration requires the support of many key components, and key components such as intensifiers and gratings still need to be developed. Conclusions and Prospects Raman spectroscopy is a very powerful tool for detecting the composition of astronomical matters and is being applied by increasingly more deep space exploration missions. At present, the development trend of Raman spectroscopy technology for deep space exploration is modularization and miniaturization, multi-technology joint detection, long-range and short-range joint detection, and diversified detection fields. © 2023 Chinese Optical Society. All rights reserved.
  Accession Number: 20232014081253
• Record 343 of
  
  Title:Correction Method of Inter Satellite Angular Distance Based on Aberration Effect
  
  Author(s):Zhang, Kaisheng(1,2); Su, Xiuqin(1); Liu, Kai(1)
  Source: Guangzi Xuebao/Acta Photonica Sinica  Volume: 52  Issue: 7  Article Number: 0712001  DOI: 10.3788/gzxb20235207.0712001  Published: July 2023  
  Abstract:Star sensors are high-precision space attitude measurement devices used in astronomical navigation to obtain the attitude of space vehicles by observing the angular distance of stars. As a key technical parameter of star simulators，the angular distance between stars is an important indicator of their testing accuracy. It represents the angular position relationship between any two-star points，and its size depends on the position of each star point. As an important component of a star simulator，optical systems can cause changes in star position due to coma，field curvature，astigmatism，and distortion. These changes can lead to discrepancies between the calculated inter-star angular distance and the theoretical inter-star angular distance，thereby affecting the accuracy of the simulation. Therefore，studying the impact of optical system aberrations on the inter-star angular distance is an important guarantee for ensuring the high accuracy of the star simulator. In order to effectively improve the accuracy of the star simulator，this paper addresses the issue that the conventional mathematical formula for calculating the inter-star angular distance does not account for the impact of aberrations in optical systems. As a solution，a method for correcting the inter-star angular distance based on aberration influence is proposed in this study. The method involves establishing a relevant mathematical model and deriving the corresponding mathematical formula. Then，taking the star simulator platform of spherical screen projection as an example，analysis and experimental testing were conducted. The test results showed the following maximum impacts of various aberrations on the inter-star angular distance：−10.04″for coma aberration，−13.07″for field curvature，− 2.92″for astigmatism，and 34.78″for distortion. Considering the compensation of each aberration on inter-star angular distance，the maximum total error of the influence of aberration on inter-satellite angular distance is 16.53″. Combining the established mathematical model of inter-satellite angular distance，curve fitting is performed on the azimuth and elevation angles of each star point to obtain a fitting curve for the position error of the star point affected by aberration，thereby completing inter-satellite angular distance correction. The experimental results show that the inter-satellite angular distance error before correction is 27.56″，and the inter-satellite angular distance error after correction is 16.96″，which is reduced by 10.60″ compared to the before correction. The research and experimental verification of inter-satellite angular distance correction methods for aberration effects provide a theoretical basis for effectively improving the simulation accuracy of satellite simulators. © 2023 Chinese Optical Society. All rights reserved.
  Accession Number: 20233714721516
• Record 344 of
  
  Title:Error Analysis and Parameters Optimization of Integrated Light-screen Array Measurement
  
  Author(s):Yu, Guodong(1); Wang, Chunyang(1); Feng, Jianghai(1); Zhang, Yue(1); Liu, Xiaochen(1); Li, Zhongqi(1); Cheng, Zhiyuan(2)
  Source: Guangzi Xuebao/Acta Photonica Sinica  Volume: 52  Issue: 6  Article Number: 0612003  DOI: 10.3788/gzxb20235206.0612003  Published: June 2023  
  Abstract:Due to the advantages of fast response，multiple factors metering and easy implementation，the measurement method of light-screen array has been widely used in the measurement of external ballistic flight parameters of barrel rapid-fire weapons. Compared with the separated light-screen array，the integrated light-screen array measurement model has the advantages of simplified parameters，simple model and easy to use. Aiming at the integrated light-screen array measurement model，the structure-related design parameters of the integrated light-screen array measurement model are extracted and the error propagation formula is derived to analyze the influence of different parameters on the measurement error of the projectile flight parameters. Then the simulation model is established in MATLAB according to the analysis result，and the influence law of the vertical angle α，the horizontal angle β，the target distance s and the height difference h on the flight velocity and coordinate measurement errors of the projectile is analyzed. The simulation results show that the vertical angle α mainly affect the projectile ordinate measuring error. and with the increase of α，the ordinate measuring error decreases and the decreasing trend gradually weakens. The horizontal angle β mainly affect the projectile abscissa measuring error，and with the increase of β，the abscissa measuring error decreases and the decreasing trend gradually weakens. The ordinate measuring error，abscissa measuring error and velocity measuring error of the projectile are all affected by the target distance s. The measurement errors gradually decrease with the increase of s and the decreasing trend is gradually weakened. Then the optimization method of structural parameters is given. By increasing angle of light screen structure，the effective target surface detection area will be reduced，and the value range of the optimized vertical angle α and horizontal angle β is from 20° to 30°. Since large target distance is not conducive to transportation，field layout and use，it is more appropriate to choose an optimized target distance s range of 1.5~2.5 m and the height difference is 0 m. According to the error distribution law of projectile flight parameters under the influence of various parameters，typical values are assigned to each parameter in the optimized integrated light-screen array measurement model that the distance between front target and back target s=2 m，height difference h=0 m. The accurate angles of the light-screen are obtained by the calibration experiment using the method of plane fitting that vertical angle α=24.94° and horizontal angle β=24.61°. Then the measurement error distribution of projectile velocity and coordinates in the range of 1 m×1 m rectangular target surface are obtained. The results showed that the measurement error of the projectile is no more than 1.50 mm in horizontal coordinate and no more than 2.10 mm in vertical coordinate. The velocity measurement error is not large，which is 728.70 mm/s. Finally，the live verification test is carried out. Due to the influence of external field environmental factors，the measurement error obtained by the test is slightly larger than the simulation result. The live test results show that the measurement of projectile flight parameters is consistent with the simulation analysis. The maximum error of abscissa measurement is not more than 3.1 mm，the maximum error of ordinate measurement is not more than 4.8 mm，and the maximum error of velocity measurement is not more than 1.1 m/s. The results of the method presented in this paper can provide theoretical basis for the measurement error analysis and theoretical support for the engineering design of light-screen array measurement equipment，and also provide a reference for improving the flight parameter measurement accuracy of barrel weapon projectile. © 2023 Chinese Optical Society. All rights reserved.
  Accession Number: 20233014444725
• Record 345 of
  
  Title:Athermalization of star sensor optical system with large field of view and low distortion
  
  Author(s):Wang, Xingyan(1,2); Wang, Hu(1,2); Shen, Yang(1); Ma, Zehua(1,2); Yan, Haoyu(1,2)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 12557  Issue: null  Article Number: 125571N  DOI: 10.1117/12.2651770  Published: 2023  
  Abstract:Star sensor is the key measurement equipment for satellite positioning and spacecraft attitude control. It provides high-precision measurement data for spacecraft attitude control and astronomical navigation. In order to realize the accurate measurement of star positioning and spacecraft attitude by star sensor in the environment with large temperature difference in space, according to the thermal compensation theory, an athermal star sensor lens with wide band, large field of view, low distortion is designed, which can work in wide temperature range. The working band is 450nm~850nm, the F number is 1.5, the field angle is 20°, and the diameter of the pupil is 30mm. The analysis results show that the relative distortion of the system is less than 0.06%, the lateral aberration of the full field is less than 3.7μm, the surrounding full field-of-view energy ratio within φ20mm is large than 80%, and temperature range is -50℃ ~60℃. The change of relative distortion, lateral aberration, energy concentration and other indicators relative to 20℃ is no more than ±10%, which fully meets the application requirements of high-precision star sensor in space environment. © 2023 SPIE.
  Accession Number: 20230813600610
• Record 346 of
  
  Title:Research On Shutter-less Non-uniformity Correction Technology Based on Ambient Temperature
  
  Author(s):Zhou, Feng(1,2); Chen, Yaohong(1); Wang, Feng(1); Xie, Qingsheng(1); Wang, Huawei(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 12615  Issue: null  Article Number: 126151L  DOI: 10.1117/12.2673955  Published: 2023  
  Abstract:Infrared imaging technology is widely used in national defense, industry, medical and other fields. High performance infrared imaging technology is highly valued by all countries in the world. However, the inhomogeneity, the inherent characteristic of infrared image, will seriously affect the real information of the image and seriously restrict the performance of infrared imaging system. In this paper, we proposed a shutter-less non-uniformity correction (SLNUC) algorithm based on ambient temperature. The SLNUC is based on the non-uniformity correction of the collected image of HgCdTE mid-wave infrared detector. The experimental results show that the SLNUC correction algorithm can adapt to the working requirements of a wide temperature range, without affecting the output of video stream, and the non-uniformity reaches 0.17% after correction, which lays a foundation for the development of new equipment. © 2023 SPIE.
  Accession Number: 20232114139897
• Record 347 of
  
  Title:Adaptive Point Design Algorithm to Generate Toolpath in Fast Tool Servo Ultra-Precision Machining of Freeform Surface
  
  Author(s):Zhaohan, Cai(1,2); Jinpeng, Li(1); Yongjun, Xie(1); Xianglong, Mao(1,2)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 12617  Issue: null  Article Number: 1261765  DOI: 10.1117/12.2666675  Published: 2023  
  Abstract:Compared with traditional coaxial multi-reflection imaging systems, the off-axis imaging system using optical freeform has many advantages, including high design freedom, small optical system size and high energy utilization. Nowadays, optical freeform surfaces have been widely utilized in imaging and non -imaging optical systems. But correspondingly, freeform machining is more difficult than spherical and aspherical optical reflectors. In the turning process, toolpath plays a critical role because it will determine the accuracy of the machined surface. The conventional methods to generate toolpath include constant-angle method, constant-arc-length method and the combination of constant-angle and constant-arc-length methods. This article proposes a new method based on an adaptive point design algorithm (APDA) to generate a series of cutting points. It will generate the cutter's toolpath based on the tangential height changes of the ideal surface. Through the simulation, the algorithm is verified that it can achieve the same accuracy when reducing the amount of data by about 40%, compared with the traditional constant-angle method. This makes freeform machining faster and provides the basis for precision machining of large-aperture freeform surfaces. © 2023 SPIE.
  Accession Number: 20232114130365
• Record 348 of
  
  Title:Stability analysis of an angle trimmer mechanism applied to a double crystal monochromator
  
  Author(s):Jiang, Bo(1); Zhang, Zijie(2); Zhou, Shun(2); Chu, Yuanbo(2); Guo, Yifan(2)
  Source: Journal of Physics: Conference Series  Volume: 2450  Issue: 1  Article Number: 012051  DOI: 10.1088/1742-6596/2450/1/012051  Published: 2023  
  Abstract:Double crystal monochromator is the core device of the synchrotron light source beamline, for the application of double crystal monochromator trimmer mechanism not only needs a high angular adjustment resolution, but also needs a high inherent frequency to ensure its stability. In this paper, we have analyzed the inherent frequency of an angle-trimming mechanism applied to a biocrystal monochromator by the energy method, established the relationship equation between its inherent frequency and each parameter of the mechanism, and analyzed the influence of each parameter on its inherent frequency. And we establish the simulation model according to the actual installation situation to carry out finite element analysis. The results prove that the mechanism has excellent stability performance and meets the requirements of light source use. © Published under licence by IOP Publishing Ltd.
  Accession Number: 20231413833073