2024

• Record 25 of
  
  Title:Duplex-Hierarchy Representation Learning for Remote Sensing Image Classification
  
  Author Full Names:Yuan, Xiaobin(1,2); Zhu, Jingping(1); Lei, Hao(3,4); Peng, Shengjun(5); Wang, Weidong(6); Li, Xiaobin(7)

  Source Title:Sensors

  Language:English

  Document Type:Journal article (JA)

  Abstract:Remote sensing image classification (RSIC) is designed to assign specific semantic labels to aerial images, which is significant and fundamental in many applications. In recent years, substantial work has been conducted on RSIC with the help of deep learning models. Even though these models have greatly enhanced the performance of RSIC, the issues of diversity in the same class and similarity between different classes in remote sensing images remain huge challenges for RSIC. To solve these problems, a duplex-hierarchy representation learning (DHRL) method is proposed. The proposed DHRL method aims to explore duplex-hierarchy spaces, including a common space and a label space, to learn discriminative representations for RSIC. The proposed DHRL method consists of three main steps: First, paired images are fed to a pretrained ResNet network for extracting the corresponding features. Second, the extracted features are further explored and mapped into a common space for reducing the intra-class scatter and enlarging the inter-class separation. Third, the obtained representations are used to predict the categories of the input images, and the discrimination loss in the label space is minimized to further promote the learning of discriminative representations. Meanwhile, a confusion score is computed and added to the classification loss for guiding the discriminative representation learning via backpropagation. The comprehensive experimental results show that the proposed method is superior to the existing state-of-the-art methods on two challenging remote sensing image scene datasets, demonstrating that the proposed method is significantly effective. © 2024 by the authors.

  Affiliations:(1) The School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an; 710049, China; (2) The Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an; 710119, China; (3) National Key Laboratory of Human-Machine Hybrid Augmented Intelligence, Xi’an Jiaotong University, Xi’an; 710049, China; (4) Institute of Artificial Intelligence and Robotics, Xi’an Jiaotong University, Xi’an; 710049, China; (5) The State Key Laboratory of Astronautic Dynamics, China Xi’an Satellite Control Center, Xi’an; 710043, China; (6) PLA 63768, Xi’an; 710600, China; (7) The Beijing Institute of Remote Sensing Information, Beijing; 100192, China

  Publication Year:2024

  Volume:24

  Issue:4

  Article Number:1130

  DOI Link:10.3390/s24041130

  数据库ID（收录号）:20240815619383
• Record 26 of
  
  Title:Multi-Dimensional Fusion of Spectral and Polarimetric Images Followed by Pseudo-Color Algorithm Integration and Mapping in HSI Space
  
  Author Full Names:Guo, Fengqi(1,2); Zhu, Jingping(1); Huang, Liqing(2); Li, Feng(1); Zhang, Ning(3); Deng, Jinxin(1); Li, Haoxiang(1); Zhang, Xiangzhe(1); Zhao, Yuanchen(1); Jiang, Huilin(4); Hou, Xun(1)

  Source Title:Remote Sensing

  Language:English

  Document Type:Journal article (JA)

  Abstract:Spectral–polarization imaging technology plays a crucial role in remote sensing detection, enhancing target identification and tracking capabilities by capturing both spectral and polarization information reflected from object surfaces. However, the acquisition of multi-dimensional data often leads to extensive datasets that necessitate comprehensive analysis, thereby impeding the convenience and efficiency of remote sensing detection. To address this challenge, we propose a fusion algorithm based on spectral–polarization characteristics, incorporating principal component analysis (PCA) and energy weighting. This algorithm effectively consolidates multi-dimensional features within the scene into a single image, enhancing object details and enriching edge features. The robustness and universality of our proposed algorithm are demonstrated through experimentally obtained datasets and verified with publicly available datasets. Additionally, to meet the requirements of remote sensing tracking, we meticulously designed a pseudo-color mapping scheme consistent with human vision. This scheme maps polarization degree to color saturation, polarization angle to hue, and the fused image to intensity, resulting in a visual display aligned with human visual perception. We also discuss the application of this technique in processing data generated by the Channel-modulated static birefringent Fourier transform imaging spectropolarimeter (CSBFTIS). Experimental results demonstrate a significant enhancement in the information entropy and average gradient of the fused image compared to the optimal image before fusion, achieving maximum increases of 88% and 94%, respectively. This provides a solid foundation for target recognition and tracking in airborne remote sensing detection. © 2024 by the authors.

  Affiliations:(1) Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Shaanxi Key Laboratory of Information Photonic Technique, Xi’an, Xi’an, 710049, China; (2) Non Equilibrium Condensed Matter and Quantum Engineering Laboratory, The Key Laboratory of Ministry of Education, School of Physics, Xi’an, Xi’an, 710049, China; (3) Key Laboratory of Spectral Imaging Technology, Xi’an Institute of Optics and Precision Mechanics of CAS, Xi’an; 710119, China; (4) National and Local Joint Engineering Research Center of Space Optoelectronics Technology, Changchun University of Science and Technology, Changchun; 130022, China

  Publication Year:2024

  Volume:16

  Issue:7

  Article Number:1119

  DOI Link:10.3390/rs16071119

  数据库ID（收录号）:20241615921118
• Record 27 of
  
  Title:Interlayer coupled dual-layer metagratings for broadband and high-efficiency anomalous reflection
  
  Author Full Names:Luo, Yijie(1,2); Yang, Ruisheng(1,2,3); Xie, Lingyun(1,2,3); Xu, Weijie(1,2); Fan, Yuancheng(4); Wei, Zeyong(1,2,3); Wang, Zhanshan(1,2,3); Cheng, Xinbin(1,2,3)

  Source Title:Optics Express

  Language:English

  Document Type:Journal article (JA)

  Abstract:Recent progress in metagratings highlights the promise of high-performance wavefront engineering devices, notably for their exterior capability to steer beams with near-unitary efficiency. However, the narrow operating bandwidth of conventional metagratings remains a significant limitation. Here, we propose and experimentally demonstrate a dual-layer metagrating, incorporating enhanced interlayer couplings to realize high-efficiency and broadband anomalous reflection within the microwave frequency band. The metagrating facilitated by both intralayer and interlayer couplings is designed through the combination of eigenmode expansion (EME) algorithm and particle swarm optimization (PSO) to significantly streamline the computational process. Our metagrating demonstrates the capacity to reroute a normally incident wave to +1 order diffraction direction across a broad spectrum, achieving an average efficiency approximately 90% within the 14.7 to 18 GHz range. This study may pave the way for future applications in sophisticated beam manipulations, including spatial dispersive devices, by harnessing the intricate dynamics of multi-layer metagratings with complex interlayer and intralayer interactions. © 2024 Optica Publishing Group.

  Affiliations:(1) Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai; 200092, China; (2) MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai; 200092, China; (3) Shanghai Frontiers Science Research Base of Digital Optics, Tongji University, Shanghai; 200092, China; (4) Department of Applied Physics, School of Science and Shenzhen Research & Development Institute, Northwestern Polytechnical University, Xi'an; 710129, China

  Publication Year:2024

  Volume:32

  Issue:12

  Start Page:21594-21605

  DOI Link:10.1364/OE.524006

  数据库ID（收录号）:20242416251695
• Record 28 of
  
  Title:Observation of 2 µm multiple annular structured vortex pulsed beams by cavity-mode tailoring
  
  Author Full Names:Zhu, Qiang(1,2); Song, Xiaozhao(1); Li, Luyao(1); Kang, Hui(1,2); Yao, Tianchen(1,2); Liu, Guangmiao(1,2); Miao, Kairui(1); Zhou, Wei(1,2); Wang, Haotian(1,2); Xu, Xiaodong(1); Jia, Baohua(3); Wang, Yishan(4); Wang, Fei(2); Shen, Deyuan(1,2)

  Source Title:Optics Letters

  Language:English

  Document Type:Journal article (JA)

  Abstract:In the past few years, annular structured beams have been extensively studied due to their unique "doughnut" structure and characteristics such as phase and polarization vortices. Especially in the 2 µm wavelength range, they have shown promising applications in fields such as novel laser communication, optical processing, and quantum information processing. In this Letter, we observed basis vector patterns with orthogonality and completeness by finely cavity-mode tailoring with end-mirror space position in a Tm:CaYAlO4 laser. Multiple annular structured beams including azimuthally, linearly, and radially polarized beams (APB, LPB, and RPB) operated at a Q-switched mode-locking (QML) state with a typical output power of ∼18 mW around 1962 nm. Further numerical simulation proved that the multiple annular structured beams are the coherent superposition of different Hermitian Gaussian modes. Using a self-made M–Z interferometer, we have demonstrated that the obtained multiple annular beams have a vortex phase with orbital angular momentum (OAM) of l = ±1. To the best of our knowledge, this is the first observation of vector and scalar annular vortex beams in the 2 µm solid-state laser. © 2024 Optica Publishing Group.

  Affiliations:(1) Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou; 221116, China; (2) Jiangsu Institute of Mid Infrared Laser Technology & Applications, Xuzhou; 221000, China; (3) The Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), RMIT University, Melbourne; VIC; 3000, Australia; (4) 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:49

  Issue:13

  Start Page:3709-3712

  DOI Link:10.1364/OL.524370

  数据库ID（收录号）:20242816657496
• Record 29 of
  
  Title:Colloidal Nanoplatelets-Based Soft Matter Technology for Photonic Interconnected Networks: Low-Threshold Lasing and Polygonal Self-Coupling Microlasers
  
  Author Full Names:Duan, Rui(1); Thung, Yi Tian(1,2); Zhang, Zitong(1,3); Durmusoglu, Emek Goksu(1,2); He, Yichen(4); Xiao, Lian(1); Lee, Calvin Xiu Xian(1); Lew, Wen Siang(1); Zhang, Lin(4); Li, Hanyang(5); Yang, Jun(6); Demir, Hilmi Volkan(1,2,7,8); Sun, Handong(1)

  Source Title:Laser and Photonics Reviews

  Language:English

  Document Type:Journal article (JA)

  Abstract:Soft matter-based microlasers are widely regarded as excellent building blocks for realizing photonic interconnected networks in optoelectronic chips, owing to their flexibility and functional network topology. However, the potential of these devices is hindered by challenges such as poor lasing stability, high lasing threshold, and gaps in knowledge regarding cavity interconnection characteristics. In this study, the first demonstration of a high-quality, low-threshold nanoplatelets (NPLs)-based polymer microfiber laser fabricated using capillary immersion techniques and its photonic interconnected networks are presented. CdSe/CdS@Cd1-xZnxS core/buffer shell@graded-shell NPLs with high optical gain characteristics are adopted as the gain medium. The study achieves a lasing threshold below 14.8 µJ cm−2, a single-mode quality (Q)-factor of ≈5500, and robust lasing stability in the fabricated NPLs-based microfibers. Furthermore, the study pioneers the exploration of polygonal self-coupling microlasers and the optical characteristics of their interconnected fiber network. Based on the signal generation mechanism observed in the photonic networks, an interconnected NPLs-based fiber network structure achieving single-mode lasing emission and laser mode modulation is successfully designed. The work contributes a novel method for realizing microlasers fabricated via soft-matter technologies and provides a key foundation and new insights for unit design and programming for future photonic network systems. © 2023 Wiley-VCH GmbH.

  Affiliations:(1) Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore; 637371, Singapore; (2) LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, The Photonics Institute, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore; 639798, Singapore; (3) Xi'an Modern Chemistry Research Institute, Shaanxi, Xi'an; 710065, China; (4) School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin; 300072, China; (5) College of Physics and Optoelectronic Engineering, Harbin Engineering University, Harbin; 150001, China; (6) Guangdong Provincial Key Laboratory of Information Photonics Technology, College of Information Engineering, Guangdong University of Technology, Guangzhou; 510006, China; (7) School of Materials Science and Engineering, Nanyang Technological University, Singapore; 639798, Singapore; (8) Department of Electrical and Electronics Engineering, Department of Physics, UNAM—Institute of Materials Science and Nanotechnology, Bilkent University, Ankara; 06800, Turkey

  Publication Year:2024

  Volume:18

  Issue:1

  Article Number:2300745

  DOI Link:10.1002/lpor.202300745

  数据库ID（收录号）:20234615068818
• Record 30 of
  
  Title:All-PM Yb-doped mode-locked fiber laser with high single pulse energy and high repetition frequency
  
  Author Full Names:Fu, Chaohui(1,2); Song, Yuanqi(1,2); Tao, Jianing(1,2); Zhang, Pu(3); Qi, Mei(4); Chen, Haowei(1,2); Bai, Jintao(1,2)

  Source Title:Journal of Optics (United Kingdom)

  Language:English

  Document Type:Journal article (JA)

  Abstract:We demonstrate an all-polarization-maintaining (PM) ytterbium (Yb)-doped fiber laser with a figure-of-9 structure to generate mode-locked pulses with high single pulse energy and high repetition frequency. By exploiting the nonlinear amplifying loop mirror, a stably self-started mode-locking is achieved with a spectrum bandwidth of 13 nm and a pulse duration of 4.53 ps. The fundamental frequency is 97.966 MHz at the maximum output power of 143 mW in single pulse mode-locked operation, corresponding to the single pulse energy is 1.46 nJ. The output pulses maintain both high repetition frequency and high single-pulse energy. This laser oscillator can be an ideal seed source for applications such as high-energy amplifiers. © 2024 IOP Publishing Ltd.

  Affiliations:(1) State Key Laboratory of Energy Photon-Technology in Western China, International Collaborative Center on Photoelectric Technology and Nano Functional materials, Institute of Photonics & Photon-technology, Northwest University, Xi’an; 710127, China; (2) Shaanxi Engineering Technology Research Center for Solid State Lasers and Application, Shaanxi Provincial Key Laboratory of Photo-electronic Technology, Northwest University, Xi’an; 710127, China; (3) State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an; 710119, China; (4) School of Information Science and Technology, Northwest University, Xi’an; 710127, China

  Publication Year:2024

  Volume:26

  Issue:7

  Article Number:075502

  DOI Link:10.1088/2040-8986/ad4612

  数据库ID（收录号）:20242216152311
• Record 31 of
  
  Title:Multi-level efficient 3D image reconstruction model based on ViT
  
  Author Full Names:Zhang, Renhao(1,2); Hu, Bingliang(1); Chen, Tieqiao(1); Zhang, Geng(1); Li, Siyuan(1); Chen, Baocheng(1,2); Liu, Jia(1,3,5); Jia, Xinyin(1); Wang, Xing(4); Su, Chang(2,4); Li, Xijie(1); Zhang, Ning(1); Qiao, Kai(2,4)

  Source Title:Optics Express

  Language:English

  Document Type:Journal article (JA)

  Abstract:Single-photon LIDAR faces challenges in high-quality 3D reconstruction due to high noise levels, low accuracy, and long inference times. Traditional methods, which rely on statistical data to obtain parameter information, are inefficient in high-noise environments. Although convolutional neural networks (CNNs)-based deep learning methods can improve 3D reconstruction quality compared to traditional methods, they struggle to effectively capture global features and long-range dependencies. To address these issues, this paper proposes a multi-level efficient 3D image reconstruction model based on vision transformer (ViT). This model leverages the self-attention mechanism of ViT to capture both global and local features and utilizes attention mechanisms to fuse and refine the extracted features. By introducing generative adversarial ngenerative adversarial networks (GANs), the reconstruction quality and robustness of the model in high noise and low photon environments are further improved. Furthermore, the proposed 3D reconstruction network has been applied in real-world imaging systems, significantly enhancing the imaging capabilities of single-photon 3D reconstruction under strong noise conditions. © 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

  Affiliations:(1) Key Laboratory of Spectral Imaging Technology of CAS, Xi’an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Xi’an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China; (3) State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou; 510301, China; (4) Key Laboratory of Ultra-fast Photoelectric Diagnostics Technology, Chinese Academy of Sciences, Xi’an; 710119, China; (5) State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou; 310012, China

  Publication Year:2024

  Volume:32

  Issue:19

  Start Page:33917-33936

  DOI Link:10.1364/OE.535211

  数据库ID（收录号）:20243817055804
• Record 32 of
  
  Title:Equivalent Mechanical Model of a Microchannel Plate
  
  Author Full Names:Zhang, Shengdan(1,2); Bai, Yonglin(1); Cao, Weiwei(1,2); Qin, Junjun(1); Gao, Jiarui(1); Chang, Le(3); Liu, Beihong(3); Hu, Zexun(4); Chu, Zhujun(3); Cong, Xiaoqing(4); Dong, Yongwei(5); Wang, Zhigang(5)

  Source Title:Measurement Science Review

  Language:English

  Document Type:Journal article (JA)

  Abstract:The microchannel plate (MCP) is an electron multiplier with millions of micro through-holes that must withstand strong vibrations and enormous shocks in spaceborne detectors. To ensure the reliability and robustness of the MCP in space applications, we proposed an equivalent mechanical model of the MCP to investigate its mechanical properties, since the direct creation of the finite element model using the finite element method (FEM) is not feasible. Then, we developed a test system to verify the effectiveness of the equivalent mechanical model. The results show that the error of harmonic response analysis and the test result is less than 10 %, which is acceptable. Finally, we conducted parametric studies of the MCPs and obtained the equivalent mechanical model of the MCPs with different geometric parameters. This study will help researchers to optimize the MCP for aerospace-grade detectors. © 2024 Shengdan Zhang et al., published by Sciendo.

  Affiliations:(1) Key Laboratory of Ultrafast Photoelectric Diagnostic Technology, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xinxi Road, No.17, Xi’an; 710119, China; (2) University of Chinese Academy of Sciences, Yanxi Lake East Road, No.1, Beijing; 100049, China; (3) North Night Vision Technology Co., Ltd., Hongwai Road, No.5, Kunming; 650217, China; (4) Nanjing Branch of North Night Vision Technology Co., Ltd., Kangping Street, No.2, Nanjing; 211102, China; (5) Institute of High Energy Physics, Chinese Academy of Sciences, Yuquan Road, No.19, Beijing; 10049, China

  Publication Year:2024

  Volume:24

  Issue:5

  Start Page:174-182

  DOI Link:10.2478/msr-2024-0023

  数据库ID（收录号）:20244617363503
• Record 33 of
  
  Title:Optical fibre based artificial compound eyes for direct static imaging and ultrafast motion detection
  
  Author Full Names:Jiang, Heng(1,2); Tsoi, Chi Chung(1,2); Yu, Weixing(3); Ma, Mengchao(4); Li, Mingjie(1); Wang, Zuankai(5); Zhang, Xuming(1,2,6)

  Source Title:Light: Science and Applications

  Language:English

  Document Type:Journal article (JA)

  Abstract:Natural selection has driven arthropods to evolve fantastic natural compound eyes (NCEs) with a unique anatomical structure, providing a promising blueprint for artificial compound eyes (ACEs) to achieve static and dynamic perceptions in complex environments. Specifically, each NCE utilises an array of ommatidia, the imaging units, distributed on a curved surface to enable abundant merits. This has inspired the development of many ACEs using various microlens arrays, but the reported ACEs have limited performances in static imaging and motion detection. Particularly, it is challenging to mimic the apposition modality to effectively transmit light rays collected by many microlenses on a curved surface to a flat imaging sensor chip while preserving their spatial relationships without interference. In this study, we integrate 271 lensed polymer optical fibres into a dome-like structure to faithfully mimic the structure of NCE. Our ACE has several parameters comparable to the NCEs: 271 ommatidia versus 272 for bark beetles, and 180o field of view (FOV) versus 150–180o FOV for most arthropods. In addition, our ACE outperforms the typical NCEs by ~100 times in dynamic response: 31.3 kHz versus 205 Hz for Glossina morsitans. Compared with other reported ACEs, our ACE enables real-time, 180o panoramic direct imaging and depth estimation within its nearly infinite depth of field. Moreover, our ACE can respond to an angular motion up to 5.6×106 deg/s with the ability to identify translation and rotation, making it suitable for applications to capture high-speed objects, such as surveillance, unmanned aerial/ground vehicles, and virtual reality. © The Author(s) 2024.

  Affiliations:(1) Department of Applied Physics, The Hong Kong Polytechnic University, 999077, Hong Kong; (2) Photonics Research Institute (PRI), The Hong Kong Polytechnic University, 999077, Hong Kong; (3) Key Laboratory of Spectral Imaging Technology, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an; 710119, China; (4) Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Opto-Electronics Engineering, Hefei University of Technology, Hefei; 230009, China; (5) Department of Mechanical Engineering, The Hong Kong Polytechnic University, 999077, Hong Kong; (6) Research Institute for Advanced Manufacturing (RIAM), The Hong Kong Polytechnic University, 999077, Hong Kong

  Publication Year:2024

  Volume:13

  Issue:1

  Article Number:256

  DOI Link:10.1038/s41377-024-01580-5

  数据库ID（收录号）:20243817075668
• Record 34 of
  
  Title:Monolithic PMN-39PT nanograting-assisted second harmonic generation enhancement
  
  Author Full Names:Li, Tianlun(1); Liu, Xin(2); Lu, Yang(3); Gao, Duorui(4); Zhang, Kai(3); Gan, Xuetao(1); Wei, Xiaoyong(2); Xu, Zhuo(2); Zhang, Lei(2)

  Source Title:Optics Express

  Language:English

  Document Type:Journal article (JA)

  Abstract:Second harmonic generation plays a vital role in frequency conversion which mutually promotes the laser technology and allows the wavebands extension of new coherent source. The monolithic crystals are supposed to be a superior choice for harmonic generation due to long interaction distance, however, the phase-mismatch brought a sharp reduction in the conversion efficiency. Although birefringent phase-matching and quasi-phase-matching techniques are commonly utilized to fill the phase gap in monolithic crystals, these techniques are limited by the natural refractive index of crystal and the domain engineering, respectively. In recent years, subwavelength structures evolve as a flexible scheme to realize phase matching by engineering the geometry features of crystals. Here, structured nanogratings are designed and fabricated on a monolithic PMN-39PT (Pb(Mg1/3Nb2/3)O3-0.39PbTiO3) substrate, a novel ferroelectric crystal with promising optical prospect, for enhancing second harmonic generation, where birefringent or quasi phase-matching is hard to achieve. The nanograting-assisted second harmonic generation enhancement is observed which is not limited by the availability of thin crystalline films. Meanwhile, a boost in the second harmonic signal synchronously promotes the cascading third harmonic generation. This method may provide an alternative solution for enhanced harmonic generation on monolithic substrates and develop potential nonlinear optical materials for frequency conversion. © 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

  Affiliations:(1) School of Microelectronics, Northwestern Polytechnical University, Xi’an; 710072, China; (2) Key Laboratory of Physical Electronics and Devices of Ministry of Education, Shaanxi Key Laboratory of Information Photonic Technique, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an; 710049, China; (3) CAS Key Laboratory of Nanophotonic Materials and Devices, Key Laboratory of Nanodevices and Applications, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou; 215123, China; (4) State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics of CAS, Xi’an; 710119, China

  Publication Year:2024

  Volume:32

  Issue:6

  Start Page:9237-9244

  DOI Link:10.1364/OE.510869

  数据库ID（收录号）:20241215768412
• Record 35 of
  
  Title:Plasma assisted pulsed laser deposition of WO3 films for thermochromism
  
  Author Full Names:Wan, Feng(1); Li, Lequn(2); Yao, Chujun(1); Jiang, Kai(3); Hu, Zhigao(3); Xu, Ning(1); Sun, Jian(1,4); Wu, Jiada(1)

  Source Title:Materials Chemistry and Physics

  Language:English

  Document Type:Journal article (JA)

  Abstract:Tungsten trioxide (WO3) is one of the extensively investigated transition metal oxides. Its excellent chromogenic properties make WO3 promising for a variety of scientific and technological applications. We report a new method for reactively depositing WO3 films by plasma assisted pulsed laser deposition that combines electron cyclotron resonance microwave discharge and pulsed laser ablation. The plasma formed during film deposition was spectroscopically characterized by optical emission measurement, revealing that the plasma contains high density of reactive gaseous oxygen and tungsten species which are essential for efficiently synthesizing WOx precursors and depositing WO3 films. The structure of the deposited films and the effect of post-deposition thermal annealing on the film structure were characterized by X-ray diffraction and Raman spectroscopy. The as-deposited WO3 film appears amorphous in nature. Annealing resulted in the growth of crystalline grains and the improvement in the crystallinity of monoclinic WO3. Optical properties of the prepared WO3 films were studied by measuring ultraviolet–visible–near infrared transmission spectra. With the increase of annealing temperature, the WO3 films show a continuous change in color, decline in transmittance, red shift in absorption edge, and narrowing in band gap, clearly manifesting the thermochromic features of the deposited WO3 films. © 2024 Elsevier B.V.

  Affiliations:(1) Engineering Research Center of Ultra-Precision Optical Manufacturing (Shanghai), Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai; 200433, China; (2) School of Optoelectronic Engineering, XiDian University, Shanxi, Xi'an; 710071, China; (3) Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Department of Materials, East China Normal University, Shanghai; 200241, China; (4) Yiwu Research Institute of Fudan University, Zhejiang, Yiwu; 322000, China

  Publication Year:2024

  Volume:314

  Article Number:128880

  DOI Link:10.1016/j.matchemphys.2024.128880

  数据库ID（收录号）:20240215360718
• Record 36 of
  
  Title:Differentiable design of freeform diffractive optical elements for beam shaping by representing phase distribution using multi-level B-splines
  
  Author Full Names:Liao, Qingming(1,2); Wang, Haoqiang(3); Feng, Zexin(1,2); Li, Mengmeng(1,2); Luo, Yi(4); Mao, Xianglong(5)

  Source Title:Optics Express

  Language:English

  Document Type:Journal article (JA)

  Abstract:The generation of a specific laser beam profile on the work surface is key to various laser beam shaping tasks, relying heavily on diffractive optical elements (DOEs). Most beam-shaping DOEs are designed using iterative Fourier transform algorithms (IFTAs), which generally have slow convergence and prone to stagnate at local minima. Moreover, the microreliefs generated by IFTAs tend to be irregular, complicating manufacturing and causing uncontrolled scattering of light. We propose a differentiable DOE design method that applies a phase-smoothness constraint using multi-level B-splines. A multi-scale gradient-descent optimization strategy, naturally linked with the multi-level B-splines, is employed to robustly determine the optimized phase distribution that is fully continuous. This, in turn, can lead to more regular DOE microreliefs, which can simplify the fabrication process and be less sensitive to changes in wavelength and working distance. Furthermore, our method can also design a fully continuous freeform lens, distinguished from most freeform lens design approaches by its foundation in physical optics rather than geometrical optics. Simulation and experimental results of several design tasks demonstrate the effectiveness of the proposed method. © 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

  Affiliations:(1) Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing; 100081, China; (2) MOE Key Laboratory of Optoelectronic Imaging Technology and Systems, Beijing Institute of Technology, Beijing; 100081, China; (3) College of Physics and Optoelectronic Engineering, Shenzhen University, Guangdong, Shenzhen; 518060, China; (4) Beijing National Research Center for Information Science and Technology, Department of Electronic Engineering, Tsinghua University, Beijing; 100084, China; (5) The New Technology Laboratory of Space Photon Information, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Shaanxi, Xi’an; 710119, China

  Publication Year:2024

  Volume:32

  Issue:23

  Start Page:41041-41056

  DOI Link:10.1364/OE.533298

  数据库ID（收录号）:20244717382307