2024

• Record 217 of
  
  Title:Depth-of-field extended Fourier ptychographic microscopy without defocus distance priori
  
  Author Full Names:Chen, Yanqi(1,2); Xu, Jinghao(1,2); Pan, An(1,2)

  Source Title:Optics Letters

  Language:English

  Document Type:Journal article (JA)

  Abstract:Fourier ptychographic microscopy (FPM) provides a solution of high-throughput phase imaging. Thanks to its coherent imaging model, FPM has the capacity of depth-of-field (DOF) extension by simultaneously recovering the sample’s transmittance function and pupil aberration, which contains a defocus term. However, existing phase retrieval algorithms (PRs) often struggle in the presence of a significant defocus. In this Letter, different PRs with embedded pupil recovery are compared, and the one based on the alternating direction multiplier method (ADMM-FPM) demonstrates promising potential for reconstructing highly defocused FPM images. Besides, we present a plug-and-play framework that integrates ADMM-FPM and total variation or Hessian denoiser for pupil function enhancement. Both simulations and experiments demonstrate that this framework enables robust reconstruction of defocused FPM images without any prior knowledge of defocus distance or sample characteristics. In experiments involving USAF 1951 targets and pathologic slides, ADMM-FPM combined with the Hessian denoiser successfully corrected the defocus up to approximately 200 µm, i.e., extending the DOF to 400 µm. © 2024 Optica Publishing Group.

  Affiliations:(1) State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China

  Publication Year:2024

  Volume:49

  Issue:11

  Start Page:3222-3225

  DOI Link:10.1364/OL.524267

  数据库ID（收录号）:20242416231469
• Record 218 of
  
  Title:Hyperspectral Image Based Interpretable Feature Clustering Algorithm
  
  Author Full Names:Kang, Yaming(1); Ye, Peishun(1); Bai, Yuxiu(1); Qiu, Shi(2)

  Source Title:Computers, Materials and Continua

  Language:English

  Document Type:Journal article (JA)

  Abstract:Hyperspectral imagery encompasses spectral and spatial dimensions, reflecting the material properties of objects. Its application proves crucial in search and rescue, concealed target identification, and crop growth analysis. Clustering is an important method of hyperspectral analysis. The vast data volume of hyperspectral imagery, coupled with redundant information, poses significant challenges in swiftly and accurately extracting features for subsequent analysis. The current hyperspectral feature clustering methods, which are mostly studied from space or spectrum, do not have strong interpretability, resulting in poor comprehensibility of the algorithm. So, this research introduces a feature clustering algorithm for hyperspectral imagery from an interpretability perspective. It commences with a simulated perception process, proposing an interpretable band selection algorithm to reduce data dimensions. Following this, a multi-dimensional clustering algorithm, rooted in fuzzy and kernel clustering, is developed to highlight intra-class similarities and inter-class differences. An optimized P system is then introduced to enhance computational efficiency. This system coordinates all cells within a mapping space to compute optimal cluster centers, facilitating parallel computation. This approach diminishes sensitivity to initial cluster centers and augments global search capabilities, thus preventing entrapment in local minima and enhancing clustering performance. Experiments conducted on 300 datasets, comprising both real and simulated data. The results show that the average accuracy (ACC) of the proposed algorithm is 0.86 and the combination measure (CM) is 0.81. © 2024 Tech Science Press. All rights reserved.

  Affiliations:(1) School of Information Engineering, Yulin University, Yulin; 719000, China; (2) Key Laboratory of Spectral Imaging Technology CAS, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an; 710119, China

  Publication Year:2024

  Volume:79

  Issue:2

  Start Page:2151-2168

  DOI Link:10.32604/cmc.2024.049360

  数据库ID（收录号）:20242116118449
• Record 219 of
  
  Title:Design of Optical System for Ultra-Large Range Line-Sweep Spectral Confocal Displacement Sensor
  
  Author Full Names:Yang, Weiguang(1,2); Du, Jian(1); Qi, Meijie(1); Yan, Jiayue(1,2); Cheng, Mohan(1,2); Zhang, Zhoufeng(1)

  Source Title:Sensors

  Language:English

  Document Type:Journal article (JA)

  Abstract:The spectrum confocal displacement sensor is an innovative type of photoelectric sensor. The non-contact advantages of this method include the capacity to obtain highly accurate measurements without inflicting any harm as well as the ability to determine the object’s surface contour recovery by reconstructing the measurement data. Consequently, it has been widely used in the field of three-dimensional topographic measuring. The spectral confocal displacement sensor consists of a light source, a dispersive objective, and an imaging spectrometer. The scanning mode can be categorized into point scanning and line scanning. Point scanning is inherently present when the scanning efficiency is low, resulting in a slower measurement speed. Further improvements are necessary in the research on the line-scanning type. It is crucial to expand the measurement range of existing studies to overcome the limitations encountered during the detection process. The objective of this study is to overcome the constraints of the existing line-swept spectral confocal displacement sensor’s limited measuring range and lack of theoretical foundation for the entire system. This is accomplished by suggesting an appropriate approach for creating the optical design of the dispersive objective lens in the line-swept spectral confocal displacement sensor. Additionally, prism-grating beam splitting is employed to simulate and analyze the imaging spectrometer’s back end. The combination of a prism and a grating eliminates the spectral line bending that occurs in the imaging spectrometer. The results indicate that a complete optical pathway for the line-scanning spectral confocal displacement sensor has been built, achieving an axial resolution of 0.8 μm, a scanning line length of 24 mm, and a dispersion range of 3.9 mm. This sensor significantly expands the range of measurements and fills a previously unaddressed gap in the field of analyzing the current stage of line-scanning spectral confocal displacement sensors. This is a groundbreaking achievement for both the sensor itself and the field it operates in. The line-scanning spectral confocal displacement sensor’s design addresses a previously unmet need in systematic analysis by successfully obtaining a wide measuring range. This provides systematic theoretical backing for the advancement of the sensor, which has potential applications in the industrial detection of various ranges and complicated objects. © 2024 by the authors.

  Affiliations:(1) Key Laboratory of Spectral Imaging Technology CAS, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China

  Publication Year:2024

  Volume:24

  Issue:3

  Article Number:723

  DOI Link:10.3390/s24030723

  数据库ID（收录号）:20240715548311
• Record 220 of
  
  Title:Effect of atmospheric environment on the stability of secondary electron emission from magnesium oxide and alumina surfaces
  
  Author Full Names:Lian, Zhuoxi(1); Zhu, Xiangping(2,3); Wang, Dan(1); Meng, Xiangchen(1); He, Yongning(1)

  Source Title:Journal of Physics D: Applied Physics

  Language:English

  Document Type:Journal article (JA)

  Abstract:MgO and Al2O3 are two typical ceramics with high secondary electron yield (SEY) and are widely applied in electron multiplier devices as dynode coating. However, dynodes in multipliers are inevitably exposed to various environments, degenerating their SEY performance. To specify the influence of the atmospheric environment on SEY for MgO and Al2O3 ceramics, we conducted environmental stability experiments on MgO and Al2O3 nanofilms. By exposing the nanofilms fabricated by atomic layer deposition to air for certain durations, it was found that although the MgO film possessed high SEY, its SEY decreased significantly as the storage duration increased, specifically, its SEY peak value (δ m) decreased from 5.97 to 3.35 after 180 d. Whereas the SEY of the Al2O3 film changed very little with the storage duration extending, its δ m decreased from 4.01 to 3.70 after 180 d, indicating the Al2O3 film had good SEY environmental stability. To reveal the mechanism of SEY degradation, the modification analysis of surface composition was implemented. It was found that the surface of MgO film underwent degradation besides unavoidable contamination, generating Mg(OH)2 and MgCO3. Whereas, there is no chemical reaction occurred on the Al2O3 surface. Combining the advantages of high SEY of MgO and good environmental stability of Al2O3, several Al2O3/MgO double-layer nanofilms were prepared. The δ m value of 20 nm MgO nanofilms covered by 1 nm Al2O3, decreased from 4.90 to 4.56, with a reduction of only 6.94% after 180 d. The results showed that the Al2O3 film achieved effective protection of the MgO film. The SEY environmental stability of the double-layer structure was significantly improved, and the effect of thickness on SEY was theoretically interpreted. This work makes significant sense for understanding the influence of the environment on the SEY for MgO and Al2O3, which has potential applications in electron multipliers. © 2023 IOP Publishing Ltd.

  Affiliations:(1) School of Microelectronics, Xi’an Jiaotong University, Xi’an; 710049, China; (2) ZhongKe Atomically Precise Manufacturing Technology Co. Ltd, Xi’an; 710119, China; (3) Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an; 710119, China

  Publication Year:2024

  Volume:57

  Issue:12

  Article Number:125302

  DOI Link:10.1088/1361-6463/ad15c0

  数据库ID（收录号）:20240115304780
• Record 221 of
  
  Title:Efficient single-cycle mid-infrared femtosecond laser pulse generation by spectrally temporally cascaded optical parametric amplification with pump energy recycling
  
  Author Full Names:Yuan, Hao(1,2); Huang, Pei(1); Feng, Tongyu(1,2); Ma, Yahui(1,2); Wang, Xianglin(1); Cao, Huabao(1,2); Wang, Yishan(1,2); Zhao, Wei(1,2); Fu, Yuxi(1,2)

  Source Title:Optics Letters

  Language:English

  Document Type:Journal article (JA)

  Abstract:We proposed spectrally temporally cascaded optical parametric amplification (STOPA) using pump energy recycling to simultaneously increase spectral bandwidth and conversion efficiency in optical parametric amplification (OPA). Using BiB3O6 and KTiOAsO4 nonlinear crystals, near-single-cycle mid-infrared (MIR) pulses with maximum energy conversion efficiencies exceeding 25% were obtained in simulations. We successfully demonstrated sub-two-cycle, CEP-stable pulse generation at 1.8 µm using a four-step STOPA system in the experiment. This method provides a solution to solve the limitations of the gain bandwidth of nonlinear crystals and the low conversion efficiency in broadband OPA systems, which is helpful for intense attosecond pulse generation and strong laser field physics studies. © 2024 Optica Publishing Group.

  Affiliations:(1) Center for Attosecond Science and Technology, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Shaanxi, Xi’an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China

  Publication Year:2024

  Volume:49

  Issue:9

  Start Page:2269-2272

  DOI Link:10.1364/OL.519729

  数据库ID（收录号）:20241916073860
• Record 222 of
  
  Title:Simulation of evaporation ablation dynamics of materials by nanosecond pulse laser of Gaussian beam and flat-top beam
  
  Author Full Names:Yin, Pei-Qi(1,2); Xu, Bo-Ping(1,2); Liu, Ying-Hua(1,2); Wang, Yi-Shan(1,2); Zhao, Wei(1,2); Tang, Jie(1,2)

  Source Title:Wuli Xuebao/Acta Physica Sinica

  Language:Chinese

  Document Type:Journal article (JA)

  Abstract:Based on the established two-dimensional asymmetric model of the interaction between a nanosecond pulse laser and metallic aluminum, the effect of beam shaping on the evaporation ablation dynamics during the ablation of metallic aluminum by a nanosecond pulse laser is simulated. The results show that plasma shielding, which has a significant influence on the ablation properties of the target, occurs mainly in the middle phase and late phase of the pulse. Among the three laser profiles, the Gaussian beam has the strongest shielding effect. As the diameter of the reshaped flat-top beam increases, the shielding effect gradually weakens. The two-dimensional spatial distribution of target temperature is relatively different between ablation by a Gaussian beam and that by a flat-top beam. For the Gaussian beam, the center of the target is first heated, and then the temperature spreads in radial direction and axial direction. For the flat-top beam, due to the uniform energy distribution, the target is heated within a certain radial range simultaneously. Beam shaping has a great influence on the evaporation ablation dynamics of the target. For the Gaussian beam, the center of the target is first ablated, followed by the radial ablation. For the flat-top beam, the evaporation time of the target surface is delayed due to the lower energy density after the beam has been shaped. In addition, the target evaporates simultaneously in a certain radial range due to the more uniform distribution of laser energy. For each of the three laser profiles, the evaporation morphology of the target resembles the intensity distribution of the laser beam. The crater produced by the Gaussian beam is deep in the center and shallow on both sides, while it becomes relatively flat by the flat-top beam. © 2024 Institute of Physics, Chinese Academy of Sciences. All rights reserved.

  Affiliations:(1) State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China

  Publication Year:2024

  Volume:73

  Issue:9

  Article Number:095202-13

  DOI Link:10.7498/aps.73.20231625

  数据库ID（收录号）:20241916068119
• Record 223 of
  
  Title:DC-KD: double-constraint knowledge distillation for optical satellite imagery object detection based on YOLOX model
  
  Author Full Names:Yang, Hongbo(1,2); Qiu, Shi(1); Feng, Xiangpeng(1)

  Source Title:Proceedings of SPIE - The International Society for Optical Engineering

  Language:English

  Document Type:Conference article (CA)

  Conference Title:4th International Conference on Machine Learning and Computer Application, ICMLCA 2023

  Conference Date:November 3, 2023 - November 5, 2023

  Conference Location:Hangzhou, China

  Conference Sponsor:Academic Exchange Information Centre (AEIC)

  Abstract:Object detection is an important application of optical satellite remote sensing imagery interpretation. Since the objects of interest, such as aircraft, ships, and vehicles, are small in size with obscure contour and texture, it is difficult for object detection in satellite images. The spatial resolution of aerial images is higher than satellite images, and the object detection model can achieve higher precision. Knowledge distillation has been validated as an effective technique by learning the common features of aerial and satellite images to improve the precision of object detection in satellite images. It means that a teacher model pre-trained on aerial image datasets guides the training of a compact student model on satellite image datasets. However, there are data distribution differences between aerial images and satellite images. The distribution differences may cause the teacher model to give guidance signals that deviate from the ground truth, thus leading to sub-optimization of the student model. In this paper, we proposed a new distillation scheme, termed DC-KD, which updates the teacher model using the predictions of the teacher model that are inconsistent with the ground truth, and the rest are used to guide the training of the student model. We achieved a 3.88% mAP50 improvement on the xView dataset based on the YOLOX-S model. © 2024 SPIE.

  Affiliations:(1) Key Laboratory of Spectral Imaging Technology CAS, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science, Xi'an, China; (2) University of Chinese Academy of Sciences, Beijing, China

  Publication Year:2024

  Volume:13176

  Article Number:131761V

  DOI Link:10.1117/12.3029285

  数据库ID（收录号）:20242316199229
• Record 224 of
  
  Title:Inverse design of high efficiency and large bandwidth power splitter for arbitrary power ratio based on deep residual network
  
  Author Full Names:Wen, Jin(1,2); Wu, Zhengwei(1); Zhang, Hui(1); Wang, Qian(1); Yu, Huimin(1); Zhang, Ying(1); Pan, Yu(1); Liu, Zhanzhi(1)

  Source Title:Optical and Quantum Electronics

  Language:English

  Document Type:Journal article (JA)

  Abstract:In this research, we propose the deep Residual Network to realize the inverse design of a low loss 1 × 3 port power splitter with an area of 2.6 × 2.6 μm2 on a standard silicon-on-insulator platform. Then the area is used as the inverse design region and discretized into 20 × 20 square pixels, where each pixel can be switched between the two random initial states of silicon square with and without holes. Besides, we use the direct binary search algorithm to change the state of the pixels so that the distribution of all pixels in the inverse design region reaches the optimal value of the algorithm. While training the network, inputting spectral transmission response, and using the etched hole vector positions as a label for the inverse design, it achieved an accuracy of 0.9111 and a correlation coefficient greater than 0.88 for all three ports. Finally, we demonstrated 1 × 3 power splitters with 1:2:1, 1:2:1.5, 1:3:1, and 1:3:2 distribution ratios and a more than 90% maximum transmission efficiency with bandwidth from 1450 to 1650 nm while having a low insertion loss of less than 0.45 dB. This research can be found potential applications in the design of photonic devices with high performance and small size. © 2024, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

  Affiliations:(1) School of Science, Xi’an Shiyou University, Xi’an; 710065, China; (2) State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an; 710119, China

  Publication Year:2024

  Volume:56

  Issue:4

  Article Number:512

  DOI Link:10.1007/s11082-023-06165-x

  数据库ID（收录号）:20240515480379
• Record 225 of
  
  Title:Bit Error Rate Performance Study of UWOC System Based on Multiple Degenerate Composite Channels
  
  Author Full Names:Zhang, Jianlei(1); Zhang, Pengwei(1); Zhu, Yunzhou(2); Tian, Yuxin(1); Li, Jieyu(1); Yang, Yi(1); He, Fengtao(1)

  Source Title:Guangzi Xuebao/Acta Photonica Sinica

  Language:Chinese

  Document Type:Journal article (JA)

  Abstract:Underwater Wireless Optical Communication (UWOC) capitalizes on the blue-green segment of the light spectrum which is subject to minimal attenuation in marine environments, thereby rendering it optimal for the conveyance of information. The advantages of UWOC are manifold, it boasts of swift data transmission, negligible latency, and fortified confidentiality. However, UWOC grapples with significant barriers which encompass the limitation of transmission range and the deleterious effects attributable to the intrinsic properties of seawater, as well as marine turbulence-factors like absorption, scattering, bubbles and turbulence that collectively compromise communicative efficiency. To systematically confront these impediments and to gauge the comprehensive influence of the aforementioned factors on UWOC system efficacy, this inquiry has formulated an integrative underwater wireless optical channel model. This archetype not only encapsulates solitary influences but also their concomitant interactions and aggregate impact on signal transmission. By harnessing the Mie scattering theorem, the research meticulously delineates the volume scattering function, the scattering coefficient, and the phase function of microbubble assemblages in seawater—pivotal determinants essential for the assessment of scattering phenomena on the propagation of optical signals. Addressing turbulence, an elaborate channel model featuring a mixed exponential generalized Gamma distribution is employed, defining the statistical behavior of turbulence to faithfully represent the stochastic and unpredictable nature of the channel. This study extends its analysis to include the repercussion of signal attenuation and acoustic noise as a consequence of turbulence, effectively projecting these perturbations onto the optical signals disseminated through the composite channel. Importantly, it elucidates a closed-form expression for the Bit Error Ratio (BER) within the composite channel, employing On-Off Keying (OOK) modulation, thus establishing a theoretical groundwork for the analysis of UWOC system performance. The research delves into the impact of critical determinants such as turbulence strength, bubble density, transmission range, and marine water quality on the BER metrics of UWOC systems. It is discerned that heightened turbulence intensity incrementally necessitates a greater minimum Signal to Noise Ratio (SNR) at the receiver end to maintain a predetermined average BER. Consistent with this SNR, an augmentation in turbulence intensity conspicuously degrades system throughput, inducing a systematic deterioration in BER performance. Within a transparent seawater milieu at a transmission span of 20 m, with a bubble concentration of 3 × 106 per cubic volume, the system′s mean BER is recorded at 4.57 × 10-4. As the bubble density escalates to 9 × 106 and subsequently to 9 × 107 per cubic volume, the average BER correspondingly declines to 5.76 × 10-4 and 1.19 × 10-2. In scenarios of turbulence characterized by a scintillation index of 1.932 8, the system is adept at sustaining low BER transmissions. Ensuring dependable communication quality with an average BER falling below 10-3 across an array of aquatic environments—be it crystalline seawater, littoral waters, or murky harbor waters—the utmost permissible transmission distances with bubble presence(at a density of 1 × 107 per cubic volume)are confined to 22.5 m, 10.4 m, and 2.3 m respectively. Absent bubble interference, these distances are extendable to 28.0 m, 13.5 m, and 2.7 m. Given the pronounced absorption and scattering induced by elevated turbidity and suspended particulates, securing long-range communication in silt-laden harbor waters presents a significant hurdle. Additionally, the study substantiates that elevating the link distance precipitates an almost linear augmentation in BER, indicative of a noteworthy degeneration in signal integrity. The outcomes not only underscore the exigency of crafting and fine-tuning UWOC systems attuned to the vicissitudes of the oceanic realm but also accentuate the latent efficacy of modulation methodologies and channel coding strategies as instrumental in amplifying system competence. © 2024 Chinese Optical Society. All rights reserved.

  Affiliations:(1) School of Electronic Engineering, Xi′an University of Posts and Telecommunications, Xi′an; 710072, China; (2) Xi′an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi′an; 710119, China

  Publication Year:2024

  Volume:53

  Issue:3

  Article Number:0301002

  DOI Link:10.3788/gzxb20245303.0301002

  数据库ID（收录号）:20241215775065
• Record 226 of
  
  Title:Prediction of Cognitive Impairment in Epilepsy Patients Based on EEG Signal with Residual Block-Based Network
  
  Author Full Names:Rong, Yan(1); Wang, Yuqi(1); Wei, Xiaojie(1); Feng, Li(2); Hu, Bingliang(1); Wang, Quan(1)

  Source Title:2024 9th International Conference on Computer and Communication Systems, ICCCS 2024

  Language:English

  Document Type:Conference article (CA)

  Conference Title:9th International Conference on Computer and Communication Systems, ICCCS 2024

  Conference Date:April 19, 2024 - April 22, 2024

  Conference Location:Xi'an, China

  Conference Sponsor:Chang'an University; IEEE

  Abstract:Mild cognitive impairment (MCI) is an irreversible, gradual neurological disease and one of the main complications of epilepsy. The scale proves effective in detecting cognitive impairment, but it relies on labor-intensive processes and is easily affected by patients' subjective behavior. Using machine learning methods to analyze EEG data is a promising alternative for detecting MCI. However, the increasing amount of EEG data affects the efficiency of detection. We innovatively propose a novel deep learning (DL) network based on residual blocks to overcome this issue. The DL network aims to efficiently detect cognitive impairment in epilepsy patients by analyzing unique EEG data collected during the Attention Network Test (ANT) and predicting patients' scale score. The suggested network consists of four phases: band-pass filter, spatial convolution block, residual block, and classifier. The entire proposed framework comprises four steps: collecting EEG data, preprocessing the raw data, extracting data features, and classification between MCI subjects and normal ones. Data from 92 patients with epilepsy were used for training and performance evaluation of the network. The classification performance of the proposed network has been compared with that of ResNet18, ResNet34, EEGNet, and FBCNet. The experimental results shows that the proposed network achieved the best classification performance among all five tested networks. The proposed network could also be used for MCI prediction, in which task it achieved about 0.05 in MAE while predicting the score of MOCA for patients, demonstrating a considerable predictive result. Five-fold cross-validation was used to assess the framework's stability. © 2024 IEEE.

  Affiliations:(1) Xi'an Institute of Optics and Precision Mechanics, Laboratory of Spectral Imaging Technology, Chinese Academy of Sciences, Xi'an, China; (2) South University, Xiangya Hospital of Central, Department of Neurology, Changsha, China

  Publication Year:2024

  Start Page:500-506

  DOI Link:10.1109/ICCCS61882.2024.10603033

  数据库ID（收录号）:20243416904442
• Record 227 of
  
  Title:Attosecond-precision timing jitter measurement based on temporal sampling method
  
  Author Full Names:Liu, Keyang(1); Li, Jinhui(1,2); Wang, Xingguo(1); Wang, Xianglin(1,2); Wang, Yishan(1,2); Zhao, Wei(1,2); Cao, Huabao(1,2); Fu, Yuxi(1,2)

  Source Title:Optics Express

  Language:English

  Document Type:Journal article (JA)

  Abstract:We propose a timing jitter measurement scheme based on the temporal sampling method. This scheme offers a wide dynamic range and high measurement accuracy for measuring timing jitter between pulses, allowing for attosecond precision in measuring timing jitter of ultrashort pulses with short and long pulse duration. By utilizing a balanced measuring configuration, this scheme is naturally immune to the environmental and laser amplitude noises, and has been successfully used to measure timing jitter of two femtosecond pulses. This scheme can be utilized to measure and control timing jitter in the beam combining systems for generation of ultrafast laser, with high average and peak powers. © 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

  Affiliations:(1) Center for Attosecond Science and Technology, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Shaanxi, Xi’an; 710119, China; (2) University of Chinese Academy of Science, Beijing; 100049, China

  Publication Year:2024

  Volume:32

  Issue:22

  Start Page:39593-39599

  DOI Link:10.1364/OE.541203

  数据库ID（收录号）:20244417298214
• Record 228 of
  
  Title:Active Compensation of Reflector Antenna Structural Deformation Based on Deep BP-Neural Network
  
  Author Full Names:Zheng, Tianxiang(1); Xiang, Binbin(1); Lin, Shangmin(2); Wang, Wei(3); Lian, Peiyuan(3); Cui, Hanwei(1)

  Source Title:2024 IEEE 7th International Conference on Electronic Information and Communication Technology, ICEICT 2024

  Language:English

  Document Type:Conference article (CA)

  Conference Title:7th IEEE International Conference on Electronic Information and Communication Technology, ICEICT 2024

  Conference Date:July 31, 2024 - August 2, 2024

  Conference Location:Xi'an, China

  Abstract:The active reflector is a method used to compensate for the surface deformation of the reflector due to gravity and other factors, which will lead to the degradation of the electromagnetic performance of the antenna. The time-invariant surface deformation of large antenna caused by wind cannot be compensated quickly and effectively. A method based on deep BP neural network (DBPNN) is proposed to quickly obtain the adjustment of active reflector actuators. The mapping relationship between the deformation of the primary reflector and the adjustment of thousands of actuators is established. In order to ensure the unity of data dimension, the relation matrix of the actuators and panels is established. By processing the deformation data of the primary reflector, the deformation and position characteristics of the panels are obtained, and the network parameters are trained by the Adam optimizer. The results show that the proposed method can obtain thousands of actuator adjustments at different elevation angles very quickly under the premise of meeting the accuracy requirements. Compared with the traditional numerical algorithm, this method is suitable for compensating the loss performance at all elevation angles, and the time of calculation is reduced significantly. © 2024 IEEE.

  Affiliations:(1) Xinjiang University, School of Mechanical Engineering, Urumqi, China; (2) Xi'an Institute of Optics and Precision Mechanics of CAS, Space Optics Technology Department, Xi'an, China; (3) Xidian University, School of Mechano-Electronic Engineering, Xi'an, China

  Publication Year:2024

  Start Page:267-270

  DOI Link:10.1109/ICEICT61637.2024.10671154

  数据库ID（收录号）:20244117164580