2024

• Record 25 of
  
  Title:TYCOS: A Specialized Dataset for Typical Components of Satellites
  
  Author(s):Bian, He; Cao, Jianzhong; Zhang, Gaopeng; Zhang, Zhe; Li, Cheng; Dong, Junpeng
  Source: APPLIED SCIENCES-BASEL  Volume: 14  Issue: 11  DOI: 10.3390/app14114757  Published: 2024  
  Abstract:The successful detection of key components within satellites is a crucial prerequisite for executing on-orbit capture missions. Due to the inherent data-driven functionality, deep learning-based component detection algorithms rely heavily on the scale and quality of the dataset for their accuracy and robustness. Nevertheless, existing satellite image datasets exhibit several deficiencies, such as the lack of satellite motion states, extreme illuminations, or occlusion of critical components, which severely hinder the performance of detection algorithms. In this work, we bridge the gap via the release of a novel dataset tailored for the detection of key components of satellites. Unlike the conventional datasets composed of synthetic images, the proposed Typical Components of Satellites (TYCOS) dataset comprises authentic photos captured in a simulated space environment. It encompasses three types of satellite, three types of key components, three types of illumination, and three types of motion state. Meanwhile, scenarios with occlusion in front of the satellite are also taken into consideration. On the basis of TYCOS, several state-of-the-art detection methods are employed in rigorous experiments followed by a comprehensive analysis, which further enhances the development of space scene perception and satellite safety.
  Accession Number: 4757
  ISSN:
  eISSN: 2076-3417
• Record 26 of
  
  Title:Spectral-interferometry-based diff-iteration for high-precision micro-dispersion measurement
  
  Author(s):Du, Wei; Huang, Jingsheng; Wang, Yang; Zhao, Maozhong; Li, Juan; He, Juntao; Wang, Jindong; Zhang, Wenfu; Zhu, Tao
  Source: PHOTONICS RESEARCH  Volume: 12  Issue: 6  DOI: 10.1364/PRJ.523314  Published: 2024  
  Abstract:Precise measurement of micro-dispersion for optical devices (optical fiber, lenses, etc.) holds paramount significance across domains such as optical fiber communication and dispersion interference ranging. However, due to its complex system, complicated process, and low reliability, the traditional dispersion measurement methods (interference, phase shift, or time delay methods) are not suitable for the accurate measurement of micro-dispersion in a wide spectral range. Here, we propose a spectral-interferometry-based diff-iteration (SiDi) method for achieving accurate wide-band micro-dispersion measurements. Using an optical frequency comb, based on the phase demodulation of the dispersion interference spectrum, we employ the carefully designed SiDi method to solve the dispersion curve at any position and any order. Our approach is proficient in precisely measuring micro-dispersion across a broadband spectrum, without the need for cumbersome wavelength scanning processes or reliance on complex high-repetitionrate combs, while enabling adjustable resolution. The efficacy of the proposed method is validated through simulations and experiments. We employed a chip-scaled soliton microcomb (SMC) to compute the dispersion curves of a 14 m single-mode fiber (SMF) and a 0.05 m glass. Compared to a laser interferometer or the theoretical value given by manufacturers, the average relative error of refractive index measurement for single-mode fiber (SMF) reaches 2.8 x 10-6 and for glass reaches 3.8 x 10-6. The approach ensures high precision, while maintaining a simple system structure, with realizing adjustable resolution, thereby propelling the practical implementation of precise measurement and control-dispersion. (c) 2024 Chinese Laser Press
  Accession Number:
  ISSN: 2327-9125
  eISSN:
• Record 27 of
  
  Title:Stress-Induced Polarization-Maintaining Large-Mode-Area Photonic Crystal Fibers With Deviation of the Single-Mode Transmission Band and Delocalization of Higher-Order Modes
  
  Author(s):Ma, Yuan; Wan, Rui; Yang, Huanhuan; Li, Yanfu; Chen, Chao; Wang, Pengfei
  Source: IEEE PHOTONICS JOURNAL  Volume: 16  Issue: 3  DOI: 10.1109/JPHOT.2024.3395776  Published: 2024  
  Abstract:The nonlinear effects and laser-induced optical and thermal damage in optical fibers, together with the limitations of beam quality and mode-field area, restrict the power scaling-up of single-mode output for developing high-power fiber lasers in the kilowatt and above range. The design of photonic crystal fibers (PCFs) with large mode areas is an effective way to address this problem. In this paper, the demands and challenges of designing very large-mode-area (VLMA-) PCFs are discussed, including the overall fiber structure design and property simulation, especially the precise definition of single-mode operating conditions of VLMA-PCFs. Finally, an advanced stress-induced polarization-maintaining, Yb-doped, PCF structure with a large mode area realized by introducing both leakage channels and higher order mode-filtering units is proposed and analyzed theoretically, for which a maximum core diameter of 101 $\boldsymbol{\mu}{\text{m}}$ and single-mode field diameter of 76.33 $\boldsymbol{\mu}{\text{m}}$ at 1064 $\text{nm}$ and a birefringence value $\boldsymbol{> 10<^>{-4}}$ orders of magnitude are achieved.
  Accession Number: 7101111
  ISSN: 1943-0655
  eISSN: 1943-0647
• Record 28 of
  
  Title:Wide-angle metalens array with quadratic phase for terahertz polarization detection
  
  Author(s):Qin, Chong; Fan, Wenhui; Wu, Qi; Jiang, Xiaoqiang; Yan, Hui; Ju, Pei
  Source: PHYSICA SCRIPTA  Volume: 99  Issue: 6  DOI: 10.1088/1402-4896/ad3d91  Published: 2024  
  Abstract:With the advances of micro/nano fabrication technology, metasurface has become an alternative to design functional devices for manipulating electromagnetic wave. Metalens is one of the basic electromagnetic functional devices that can be applied in various fields. Currently, polarization measurement based on metalens arrays has been widely investigated, but most of them can only work for normal incident wave due to the limited field-of-view of metalens. Herein, a dielectric wide-angle metalens array (WMA) for the terahertz polarization detection is presented. The WMA is composed of three wide-angle metalenses, each wide-angle metalens is constructed by utilizing quadratic phase profile. The angle tolerance of meta-atoms which constitute the wide-angle metalens is elucidated in detail. The WMA can decompose incident terahertz wave into four channels, and the full Stokes parameters of incident wave is determined by intensities in these four channels. Simulated results show that the WMA proposed here has excellent performance for the polarization detection within incident angle of +/- 40 degrees . In addition, this WMA can also be used to detect the phase gradient of incident terahertz wave, the detection error is less than 1.1%. This WMA is promising in the fields of terahertz polarization generation, detection and imaging.
  Accession Number: 65515
  ISSN: 0031-8949
  eISSN: 1402-4896
• Record 29 of
  
  Title:Enhanced optical nonlinearity of epsilon-near-zero metasurface by quasi-bound state in the continuum
  
  Author(s):Shi, Wenjuan; Wang, Zhaolu; Zhang, Changchang; Zhang, Congfu; Li, Wei; Liu, Hongjun
  Source: MATERIALS TODAY NANO  Volume: 26  Issue:   DOI: 10.1016/j.mtnano.2024.100474  Published: 2024  
  Abstract:Bound states in the continuum (BICs) provide a powerful way to enhance the nonlinear properties of materials, epsilon-near-zero (ENZ) materials are considered as promising candidates with strong nonlinearities. However, the realization of BIC based on ENZ materials in the near-infrared (NIR) is very challenging due to the large loss in the NIR. Here, a high-quality quasi -BIC based on the ENZ metasurface is proposed for the first time, which is composed of patterned ENZ films embedded in a dielectric-metal hybrid structure, and realizes destructive interference between the Berreman mode and photonic mode to form the Friedrich-Wintergen BIC (FW-BIC). The electric field is strongly confined in the ENZ film, resulting in considerable field enhancement, and the nonlinear refractive index coefficient is 1.63 x 10 -12 m 2 /W, which is three orders of magnitude larger than that of the ITO film. The instantaneous response time is 600 fs and extremely high modulation speed up to the THz level. Benefiting from the perfect absorption and narrow linewidth of quasi -BIC and the change in refractive index of the metasurface induced by Kerr nonlinearity, the absolute modulation is from near-zero to 92% with an extinction ratio of 23.2 dB. It provides a promising platform for the development of integrated ultrafast highspeed photonics.
  Accession Number: 100474
  ISSN: 2588-8420
  eISSN:
• Record 30 of
  
  Title:Dual-parameter controlled reconfigurable metasurface for enhanced terahertz beamforming via inverse design method
  
  Author(s):Wu, Qi; Fan, Wen-Hui; Qin, Chong; Jiang, Xiao-Qiang
  Source: PHYSICA SCRIPTA  Volume: 99  Issue: 6  DOI: 10.1088/1402-4896/ad43c3  Published: 2024  
  Abstract:Recently, reconfigurable metasurfaces have emerged as a promising solution for wavefront manipulation in the terahertz (THz) region, providing enhanced beamforming capabilities. However, traditional single-parameter control methods fail to achieve independent phase and amplitude modulation, constraining their modulation capabilities. Meanwhile, forward design methods based on phase matching ignore the structural responses of the non-ideal unit, leading to degraded beamforming performance. Here, we introduce an electrically reconfigurable metasurface composed of bilayer graphene strips based on dual-parameter control. Full-wave simulations demonstrate independent amplitude and phase modulation, achieving the full 360 degrees phase coverage and an adjustable amplitude range from 0 to 0.8 at 2.6 THz. To optimize beamforming performance, particularly for the responses of the non-ideal unit away from the designed frequency, we employed an inverse design method based on a hybrid evolutionary algorithm. This novel approach significantly enhances beam steering, achieving a maximum 60% increase in beam directivity and maintaining over 90% of ideal directivity across a broad frequency range from 1.6 THz to 5 THz. Especially, it achieves a maximum deflection angle of 75 degrees. Meanwhile, the adaptability of the inverse design method is further demonstrated to various optimized objectives. For beam focusing, even with limited phase control (below 210 degrees), this method significantly enhances the focusing quality (up to 150% enhancement) and increases the focusing efficiency from 25% to 40%. Additionally, it effectively mitigates the impact of quantized phase errors on beamforming. This research not only demonstrates potential applications in high-speed THz wireless communication and compact imaging systems but also paves the way for innovative designs in reconfigurable metasurfaces.
  Accession Number: 65517
  ISSN: 0031-8949
  eISSN: 1402-4896
• Record 31 of
  
  Title:Noncollinear phase matching and effective nonlinear coefficient calculations for biaxial crystal out of the principal plane
  
  Author(s):Xing, Dingding; Yi, Dongchi; Yuan, Suochao; Chen, Xiaoyi; Da, Zhengshang
  Source: APPLIED PHYSICS B-LASERS AND OPTICS  Volume: 130  Issue: 6  DOI: 10.1007/s00340-024-08247-4  Published: 2024  
  Abstract:The essential factor in laser frequency conversion involves phase matching within nonlinear optical crystals. To our knowledge, few studies have investigated the noncollinear phase matching calculation for biaxial crystal out of the principal plane. In this paper, we propose an arbitrary direction phase matching model and a computational method based on gradient descent (GD) algorithm, which can be applied to noncollinear in the principal plane, collinear and noncollinear out of the principal plane. In the case of 1053 nm third harmonic generation (THG) in LiB3O5 (LBO) crystal, the phase matching conditions are converted into a system of nonlinear equations with six variables and six equations, which can be solved by iterative optimization search with the GD algorithm and includes type-I (ss-f) and type-II (fs-f). We reveal the relationship of phase matching angles and effective nonlinear coefficients (d(eff)) for various structures. Our method uncovers the existence of many solutions in the non-principal plane with gamma > 8 degrees and the (eff) close to the maximum value 0.66834 pm/V at theta = 90 degrees, phi = 141.84 degrees and gamma = 0. The resolution of the arbitrary direction phase matching problem holds significant importance, as it expands the possibilities for laser frequency conversion, especially for noncollinear structures.
  Accession Number: 109
  ISSN: 0946-2171
  eISSN: 1432-0649
• Record 32 of
  
  Title:Multi-Objective Topology Optimization of Acquisition Pointing and Tracking System
  
  Author(s):Gao, Bo; Yang, Hongtao; Chen, Weining; Wang, Hao; Fei, Jiaqi; Qi, Zimiao

  Source: INTERNATIONAL JOURNAL OF PATTERN RECOGNITION AND ARTIFICIAL INTELLIGENCE DOI: 10.1142/S0218001424560032  Published: 2024  

  Abstract:There is a growing need for the lightweight acquisition, tracking, and pointing (APT) system during satellite launches due to the escalating demand in space missions. The APT system may work under multiple loading cases during different launch steps. Hence, this study introduces an innovative amalgamation of genetic operation and bi-directional evolutionary structural optimization (BESO) to fulfill the multi-objective requirements through the attainment of Pareto optimal fronts. A typical instance in two dimensions illustrates the effectiveness of the innovative multi-objective approach by contrasting the outcomes acquired from a solitary fulfillment requirement under two distinct burdens. Furthermore, the novel multi-objective method is utilized to remove inefficient material from the APT system by 20.12%. To ensure the safety of the lightweight design, the simulation and experiment of random vibration are both investigated according to the fundamental natural frequency of the launcher.

  Accession Number:

  ISSN: 0218-0014

  eISSN: 1793-6381
• Record 33 of
  
  Title:Design of electronic readout system for resistive anode based on FPGA
  
  Author(s):Song, Yuchao; Zhang, Wenwen; Zheng, Jinkun; Yang, Yang; Bai, Yonglin; La, Anpeng; Duan, Jinyao
  Source: IEICE ELECTRONICS EXPRESS  Volume: 21  Issue: 10  DOI: 10.1587/elex.21.20240117  Published: 2024  
  Abstract:This paper presents an electronic readout system based on the resistance anode, which is capable of processing the output signal from the resistance anode. This design divides the electronic readout circuit into two parts: analog circuit design and digital circuit design. The analog pre-processing circuit the electric charge signal from the resistive anode detector into a voltage signal and amplifies it and the digital part consists of a trapezoidal double -channel shaping algorithm implemented in FPGA. This design overcomes pulse pile-up at high count rates.
  Accession Number: 20240117
  ISSN: 1349-2543
  eISSN:
• Record 34 of
  
  Title:Streak tube imaging lidar with kilohertz laser pulses and few-photons detection capability
  
  Author(s):Fang, Mengyan; Qiao, Kai; Yin, Fei; Xue, Yanhua; Chang, Yu; Su, Chang; Wang, Zhengzheng; Tian, Jinshou; Wang, Xing
  Source: OPTICS EXPRESS  Volume: 32  Issue: 11  DOI: 10.1364/OE.520620  Published: 2024  
  Abstract:Lidar using active light illumination is capable of capturing depth and reflectivity information of target scenes. Among various technologies, streak tube imaging lidar (STIL) has garnered significant attention due to its high resolution and excellent precision. The echo signals of a STIL system using single laser pulse are often overwhelmed by noise in complex environments, making it difficult to discern the range of the target. By combining high-frequency laser pulses with the repetitive sweep circuit, the STIL system enables efficient detection of few-photons signal in weak-light environments. Additionally, we have developed a robust algorithm for estimating the depth and reflectivity images of targets. The results demonstrate that this lidar system achieves a depth resolution better than 0.5 mm and a ranging accuracy of 95 um. Furthermore, the imaging of natural scenes also validates the exceptional 3D imaging capability of this system. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
  Accession Number:
  ISSN: 1094-4087
  eISSN:
• Record 35 of
  
  Title:Single-pixel imaging based on self-supervised conditional mask classifier-free guidance
  
  Author(s):Li, Qianxi; Yan, Qiurong; Dong, Jiawei; Feng, Jia; Wu, Jiaxin; Cao, Jianzhong; Liu, Guangsen; Wang, Hao
  Source: OPTICS EXPRESS  Volume: 32  Issue: 11  DOI: 10.1364/OE.518455  Published: 2024  
  Abstract:Reconstructing high -quality images at a low measurement rate is a pivotal objective of Single -Pixel Imaging (SPI). Currently, deep learning methods achieve this by optimizing the loss between the target image and the original image, thereby constraining the potential of low measurement values. We employ conditional probability to ameliorate this, introducing the classifier -free guidance model (CFG) for enhanced reconstruction. We propose a self -supervised conditional masked classifier -free guidance (SCM-CFG) for single -pixel reconstruction. At a 10% measurement rate, SCM-CFG efficiently completed the training task, achieving an average peak signal-to-noise ratio (PSNR) of 26.17 dB on the MNIST dataset. This surpasses other methods of photon imaging and computational ghost imaging. It demonstrates remarkable generalization performance. Moreover, thanks to the outstanding design of the conditional mask in this paper, it can significantly enhance the accuracy of reconstructed images through overlay. SCM-CFG achieved a notable improvement of an average of 7.3 dB in overlay processing, in contrast to only a 1 dB improvement in computational ghost imaging. Subsequent physical experiments validated the effectiveness of SCM-CFG. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
  Accession Number:
  ISSN: 1094-4087
  eISSN:
• Record 36 of
  
  Title:Enhancement and suppression of nonsequential double ionization by spatially inhomogeneous fields
  
  Author(s):Luo, Xuan; Jiao, Li Guang; Liu, Aihua; Liu, Xueshen
  Source: OPTICS EXPRESS  Volume: 32  Issue: 11  DOI: 10.1364/OE.523593  Published: 2024  
  Abstract:Using the three-dimensional classical ensemble approach, we theoretically investigate the nonsequential double ionization of argon atoms in an intense laser field enhanced by bowtienanotip. We observe an anomalous decrease in the double ionization yield as the laser intensity increases, along with a significant gap in the low momentum of photoelectrons. According to our theoretical analysis, the finite range of the induced field by the nanostructure is the fundamental cause of the decline in double ionization yield. Driven by the enhanced inhomogeneous field, energetic electrons can escape from the finite range of nanotips without returning. This reduces the possibility of re-scattering on the nucleus and imprints the finite size effect into the double ionization yield and momentum distribution of photoelectrons in the form of yield decline and a gap in the photoelectron-momentum distribution. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
  Accession Number:
  ISSN: 1094-4087
  eISSN: