2024

• Record 13 of
  
  Title:Two-dimensional localized modes in nonlinear systems with linear nonlocality and moiré lattices
  
  Author(s):Liu, Xiuye; Zeng, Jianhua
  Source: FRONTIERS OF PHYSICS  Volume: 19  Issue: 4  DOI: 10.1007/s11467-023-1370-7  Published: 2024  
  Abstract:Periodic structures structured as photonic crystals and optical lattices are fascinating for nonlinear waves engineering in the optics and ultracold atoms communities. Moire photonic and optical lattices - two-dimensional twisted patterns lie somewhere in between perfect periodic structures and aperiodic ones - are a new emerging investigative tool for studying nonlinear localized waves of diverse types. Herein, a theory of two-dimensional spatial localization in nonlinear periodic systems with fractional-order diffraction (linear nonlocality) and moire optical lattices is investigated. Specifically, the flat-band feature is well preserved in shallow moire optical lattices which, interact with the defocusing nonlinearity of the media, can support fundamental gap solitons, bound states composed of several fundamental solitons, and topological states (gap vortices) with vortex charge s = 1 and 2, all populated inside the finite gaps of the linear Bloch-wave spectrum. Employing the linear-stability analysis and direct perturbed simulations, the stability and instability properties of all the localized gap modes are surveyed, highlighting a wide stability region within the first gap and a limited one (to the central part) for the third gap. The findings enable insightful studies of highly localized gap modes in linear nonlocality (fractional) physical systems with shallow moire patterns that exhibit extremely flat bands.
  Accession Number: 42201
  ISSN: 2095-0462
  eISSN: 2095-0470
• Record 14 of
  
  Title:Structural vibration frequency monitoring based on event camera
  
  Author(s):Lv, Yuanyuan; Zhou, Liang; Liu, Zhaohui; Zhang, Haiyang
  Source: MEASUREMENT SCIENCE AND TECHNOLOGY  Volume: 35  Issue: 8  DOI: 10.1088/1361-6501/ad42bf  Published: 2024  
  Abstract:Compared with traditional cameras, event cameras (ECs) have the significant advantages of high temporal resolution, low data redundancy, and microsecond delay, which are beneficial in structural monitoring to extract the dense response of structures in both spatial and temporal dimensions. In this paper, the vibration frequency detection method based on ECs is studied. This study investigates vibration frequency detection methods based on ECs, and proposes two algorithms for vibration frequency detection based on event streams: marker tracking and event count. Experimental verification is conducted through forced vibration experiments. The results indicate that the event count method achieves high-precision measurement of vibration frequencies in the range of 10-190 Hz for different vibration scales, with a maximum relative error of 1% and an average relative error of 0.673%. The marker tracking method demonstrates a maximum relative error of 1.43% and an average relative error of 0.575% in frequency measurement for large-amplitude vibrations. However, as the amplitude decreases, the frequency measurement error increases. When the amplitude is less than 3 pixels, the frequency measurement error exceeds 30%, rendering the measurement results unreliable. This research provides technical support for high-precision structural vibration frequency monitoring and further expands the application of ECs in structural monitoring.
  Accession Number: 85007
  ISSN: 0957-0233
  eISSN: 1361-6501
• Record 15 of
  
  Title:Analysis of InGaAs/InP Single Photon Avalanche Diodes With Multiplication Width in Sub-Micron
  
  Author(s):Qiao, Kai; Chang, Yu; Xu, Zefang; Yin, Fei; Liu, Liyu; Wang, Jieying; Su, Chang; Xu, Linmeng; Fang, Mengyan; Liu, Chunliang; Tian, Jinshou; Wang, Xing
  Source: IEEE JOURNAL OF QUANTUM ELECTRONICS  Volume: 60  Issue: 4  DOI: 10.1109/JQE.2024.3399176  Published: 2024  
  Abstract:InGaAs/InP single-photon avalanche photodiodes (SPADs) is capable of detecting single-photon in the near-infrared spectrum for applications such as quantum communication, fluorescence lifetime imaging, and Light detection and ranging(LIDAR). The effect of multiplication layer width on the performance of SPADs in both linear and Geiger mode have been theoretically studied. Three-types of InGaAs/InP planer SPADs with different multiplication width are fabricated and evaluated. The results of this study suggest that modifying the width of the multiplication layer can regulate the breakdown voltage, punch-through voltage, and dark current of the device. It is found that the measured time jitter is decreasing with the reduction of the width of the multiplication region. These characteristics can be used to optimize the temporal resolution of SPADs device.
  Accession Number: 4500107
  ISSN: 0018-9197
  eISSN: 1558-1713
• Record 16 of
  
  Title:Influencing mechanisms of hot isostatic pressing on surface properties of additively manufactured AlSi10Mg alloy
  
  Author(s):Sun, Lijun; Yang, Yulei; Li, Siyuan; Chen, Wencong; Wang, Yichun; Yan, Peng; Zhu, Yueqi; Wu, Weichao; Hu, Bingliang
  Source: JOURNAL OF MATERIALS PROCESSING TECHNOLOGY  Volume: 329  Issue:   DOI: 10.1016/j.jmatprotec.2024.118426  Published: 2024  
  Abstract:Additively manufactured AlSi10Mg alloys have received considerable attention due to the prospectives in lightweight structural applications. Hot isostatic pressing (HIP) is widely utilized to minimize internal pores and enhance mechanical properties in terms of fatigue strength and ductility. Whereas the influence and mechanisms of HIP on surface properties, which is of crucial importance for aerospace optical components, remain to be further clarified. In the present study, systematic surface and subsurface analysis were conducted to unveil the underlying mechanisms of HIP on the surface qualities of an additively manufactured AlSi10Mg alloy. Threedimensional white-light interfering profilometer, high-resolution X-ray micro computed tomography, X-ray diffraction, scanning electron microscope and transmission electron microscope were exploited to characterize the surface and subsurface alterations induced by HIP. The results demonstrate that, although remarkable reduction in the amount and size of internal pores can be achieved, sharp increase in the surface defects and roughness occurred for the precisely machined surface of the HIP treated alloy. Surface and subsurface analysis reveal that the deterioration in surface properties results from the establishment of micron Si particles and the reduction in nanohardness induced by HIP treatment.
  Accession Number: 118426
  ISSN: 0924-0136
  eISSN: 1873-4774
• Record 17 of
  
  Title:A painting authentication method based on multi-scale spatial-spectral feature fusion and convolutional neural network
  
  Author(s):Zeng, Zimu; Zhang, Pengchang; Qiu, Shi; Li, Siyuan; Liu, Xuebin
  Source: COMPUTERS & ELECTRICAL ENGINEERING  Volume: 118  Issue:   DOI: 10.1016/j.compeleceng.2024.109315  Published: 2024  
  Abstract:The scientific authentication of paintings holds significant importance within the realm of art collection. Employing convolutional neural networks for the classification of authentic and counterfeit painting images based on color images is a viable but suboptimal choice. This study investigates the potential for authenticating paintings by incorporating high-spectral images alongside high-resolution spatial images. High-resolution and high-spectral images of genuine and counterfeit paintings were acquired using a push-broom digital scanning system. The processing methods presented in this approach for the acquired images are: 1) The study utilized the circular local binary pattern (LBP) and principal component analysis (PCA) to extract surface texture and spectral data from Chinese character images in paintings, encompassing both spatial and spectral dimensions. 2) The technique utilizing non-subsampling Shearlet transform (NSST) and pulse-coupled neural network (PCNN) was employed to integrate the spatial and spectral characteristics of the images into a pseudo-color image, producing a dataset of feature data for genuine and counterfeit paintings. 3) The experiments aimed to achieve the authenticity of artworks using EfficientNet v2-s, the hyperparameters of which were fine-tuned accordingly. The experimental findings demonstrate that this approach attained a 90.8 % accuracy on the test dataset, representing a 3.5 % enhancement over the existing top-performing three-dimensional convolutional neural network (3D-CNN).
  Accession Number: 109315
  ISSN: 0045-7906
  eISSN: 1879-0755
• Record 18 of
  
  Title:All-PM Yb-doped mode-locked fiber laser with high single pulse energy and high repetition frequency
  
  Author(s):Fu, Chaohui; Song, Yuanqi; Tao, Jianing; Zhang, Pu; Qi, Mei; Chen, Haowei; Bai, Jintao
  Source: JOURNAL OF OPTICS  Volume: 26  Issue: 7  DOI: 10.1088/2040-8986/ad4612  Published: 2024  
  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.
  Accession Number: 75502
  ISSN: 2040-8978
  eISSN: 2040-8986
• Record 19 of
  
  Title:High refractive index chalcogenide polymer-based planar refractive microlens components
  
  Author(s):Liu, Feng; Zhang, Jiawei; Guo, Zhaojin; Zhou, Liang; Li, Xianda; Lei, Xiaowei; Ji, Ruonan; Zhang, Jiwei; Li, Peng; Liu, Sheng; Zhu, Xiangping; Zhao, Jianlin
  Source: OPTICS AND LASERS IN ENGINEERING  Volume: 178  Issue:   DOI: 10.1016/j.optlaseng.2024.108200  Published: 2024  
  Abstract:Planar microlens components are highly desired in micro-systems for their compactness and ability to integrate with other planar elements. In this paper, we propose an alternative facile approach to producing positive planar microlens components by infilling concave microlens featured glass encapsulation with high refractive index chalcogenide polymer. The presented refractive microlens components have several advantages: cost-efficient to process, high transmission in broadband spectrum, the ability to generate real focus and real image, and being well-protected by its planar glass encapsulation. Both single and arrayed samples were fabricated to demonstrate the effectiveness of the manufacturing process. The optical properties of the fabricated samples, including phase modulation, imaging performance, and spectrally operational region, were thoroughly characterized. Wavefront calibration with the prepared sample revealed its potential application in practical engineering fields.
  Accession Number: 108200
  ISSN: 0143-8166
  eISSN: 1873-0302
• Record 20 of
  
  Title:An innovative 16-bit projection display based on quaternary hybrid light modulation
  
  Author(s):Pan, Yue; Cao, Yajie; Xu, Liang; Hu, Motong; Jiang, Qing; Li, Shuqin; Lu, Xiaowei
  Source: OPTICS AND LASERS IN ENGINEERING  Volume: 178  Issue:   DOI: 10.1016/j.optlaseng.2024.108171  Published: 2024  
  Abstract:Conventional spatial light modulators (SLM) can only be used for projecting 8 -bit or 10 -bit images at normal frame rate. Therefore, commercial high dynamic range (HDR) displays typically focus on boosting the contrast while neglecting to raise the bit -depth. Existing methods for high bit -depth display generally rely on stacking two SLMs to modulate the outgoing beam twice, namely multiplicative modulation, resulting in many troubles such as low optical efficiency, difficulty in pixel -level alignment, and complex image rendering algorithm. In this paper, an innovative quaternary hybrid light modulation (QHLM) based projection display is proposed and realized. By illuminating two parallel digital micro -mirror devices (DMDs) with different light intensities, the quaternary digit -planes (QDs) with four gray levels are able to be modulated rapidly. Aiming at this ability, the quaternary pulse width modulation (QPWM) is incorporated with the quaternary light -intensity modulation (QLM) to fundamentally improve the modulation efficiency compared to the binary light modulation mode. Furthermore, the quaternary digit -plane decomposition (QDD) based image splitting algorithm is adopted to split a high bit -depth image into two images that drive two DMDs respectively. The prototype is designed and built to verify the feasibility of the QHLM based projection display. The experimental results demonstrate that the prototype can project 16 -bit images at 220 fps. Through additive modulation of two DMDs in parallel, the QHLM entirely avoids the drawbacks of multiplicative modulation. As a completely different technology, the QHLM has a great potential for HDR projection applications.
  Accession Number: 108171
  ISSN: 0143-8166
  eISSN: 1873-0302
• Record 21 of
  
  Title:In-line attosecond photoelectron holography for single photon ionization
  
  Author(s):Liu, Yanhong; Cao, Wei; Yao, Ling-hui; Pi, Liang-Wen; Zhou, Yueming; Lu, Peixiang
  Source: PHYSICAL CHEMISTRY CHEMICAL PHYSICS  Volume:   Issue:   DOI: 10.1039/d3cp05919g  Published: 2024  
  Abstract:The momentum distribution of photoelectrons in H2+ molecules subjected to an attosecond pulse is theoretically investigated. To better understand the laser-molecule interaction, we develop an in-line photoelectron holography approach that is analogous to optical holography. This approach is specifically suitable for extracting the amplitude and phase of the forward-scattered electron wave packet in a dissociating molecule with atomic precision. We also extend this approach to imaging the transient scattering cross-section of a molecule dressed by a near infrared laser field. This attosecond photoelectron holography sheds light on structural microscopy of dissociating molecules with high spatial-temporal resolution. A novel method based on single photon ionization can retrieve structural dynamics of dissociating molecules by combining photoelectron holography and an attosecond pulse.
  Accession Number:
  ISSN: 1463-9076
  eISSN: 1463-9084
• Record 22 of
  
  Title:Archimedes spiral optical vortex array emitter
  
  Author(s):Ma, Xin; Wang, Ruoyu; Zhang, Hao; Tang, Miaomiao; Tai, Yuping; Li, Xinzhong
  Source: OPTICS EXPRESS  Volume: 32  Issue: 13  DOI: 10.1364/OE.523806  Published: 2024  
  Abstract:Optical vortex arrays (OVAs) are important for large -capacity optical communications, optical tweezers, and optical imaging. However, there is an urgent need to generate an optical vortex emitter to construct a specific OVA with a functional structure for the accurate transport of particles. To address this issue, we propose an Archimedes spiral OVA emitter that uses an Archimedes spiral parametric equation and coordinate localization techniques to dynamically regulate the position of each optical vortex. We discuss the phenomena of the location coordinates and Archimedes spiral from unclosed to closed on the OVA emitter. Furthermore, the propose of multiple OVA emitters demonstrates a chiral structure that has the potential for optical material processing. This study lays the foundation for generating OVAs with functional structures, which will facilitate advanced applications in the complex manipulation, separation, and transport of multiple particles. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
  Accession Number:
  ISSN: 1094-4087
  eISSN:
• Record 23 of
  
  Title:Adaptive compound control of laser beam jitter in deep-space optical communication systems
  
  Author(s):Su, Yunhao; Han, Junfeng; Wang, Xuan; Ma, Caiwen; Wu, Jianming
  Source: OPTICS EXPRESS  Volume: 32  Issue: 13  DOI: 10.1364/OE.521520  Published: 2024  
  Abstract:In deep-space optical communication systems, precise pointing and aiming of the laser beam is essential to ensure the stability of the laser link. In this paper, an adaptive compound control system based on adaptive feedforward and Proportional-Integral-Differentiation (PID) feedback is proposed. The feedforward controller is stabilized using Youla-Kucera (YK) parameterization. In the YK parameterized structure, the free parameter Q(z) consists of an adaptive filter. The proposed method constitutes an adaptive feedforward control algorithm through the adaptive filter Q(z). The problem of suppressing laser jitter is transformed into a problem of minimizing a sensitivity function containing the adaptive filter. The stability of the compound control system is ensured by configuring the individual parameters of the YK parameterized feedforward controller and the PID controller, and the adaptive regulation of the controller is realized on the premise of system stability. To verify the effectiveness of the compound control system, we established an experimental platform for laser beam stabilization control. We experimentally compare the effectiveness of the proposed control method with the classical method. The experimental results show that the method proposed in this paper can effectively suppress the complex laser beam jitter consisting of narrow-band sinusoidal and broad-band continuous vibrations.
  Accession Number:
  ISSN: 1094-4087
  eISSN:
• Record 24 of
  
  Title:Moisture-enabled self-charging and voltage stabilizing supercapacitor
  
  Author(s):Wang, Lifeng; Wang, Haiyan; Wu, Chunxiao; Bai, Jiaxin; He, Tiancheng; Li, Yan; Cheng, Huhu; Qu, Liangti
  Source: NATURE COMMUNICATIONS  Volume: 15  Issue: 1  DOI: 10.1038/s41467-024-49393-9  Published: 2024  
  Abstract:Supercapacitor is highly demanded in emerging portable electronics, however, which faces frequent charging and inevitable rapid self-discharging of huge inconvenient. Here, we present a flexible moisture-powered supercapacitor (mp-SC) that capable of spontaneously moisture-enabled self-charging and persistently voltage stabilizing. Based on the synergy effect of moisture-induced ions diffusion of inner polyelectrolyte-based moist-electric generator and charges storage ability of inner graphene electrochemical capacitor, this mp-SC demonstrates the self-charged high areal capacitance of 138.3 mF cm(-2) and similar to 96.6% voltage maintenance for 120 h. In addition, a large-scale flexible device of 72 mp-SC units connected in series achieves a self-charged 60 V voltage in air, efficiently powering various commercial electronics in practical applications. This work will provide insight into the design self-powered and ultra-long term stable supercapacitors and other energy storage devices.
  Accession Number: 4929
  ISSN:
  eISSN: 2041-1723