Optics & Laser Technology最新文献

{"title":"Synergizing deep learning and phase change materials for four-state broadband multifunctional metasurfaces in the visible range","authors":"Md. Ehsanul Karim, Md. Redwanul Karim, Sajid Muhaimin Choudhury","doi":"10.1016/j.optlastec.2024.111730","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111730","url":null,"abstract":"In this article, we report, for the first time, broadband multifunctional metasurfaces with more than four distinct functionalities. The constituent meta-atoms combine two different phase change materials, and in a multi-stage configuration. Finite-difference time-domain simulations demonstrate a broadband reflection amplitude switching between the four states in visible range due to the enhanced cavity length modulation effect from the cascaded Fabry–Perot cavities, overcoming the inherent small optical contrast between the phase change material (PCM) states. This, along with the reflection phase control between the four states, allows us to incorporate both amplitude and phase-dependent properties in the same metasurface — achromatic deflection, wavelength beam splitting, achromatic focusing, and broadband absorption, overcoming the limitations of previous functionality switching mechanisms for the visible band. We have used a Tandem Neural network-based inverse design scheme to ensure the stringent requirements of different states are realized. We have used two forward networks for predicting the reflection amplitude and phase for a meta-atom within the pre-defined design space. The excellent prediction capability of these surrogate models is utilized to train the reverse network. The inverse design network, trained with a labeled data set, is capable of efficiently navigating through the vast parametric space to produce the optimized meta-units given the desired figure-of-merits in terms of reflection amplitude and phase for the four states. The optical characteristics of two inverse-designed metasurfaces have been evaluated as test cases for two different sets of design parameters in the four states. Both structures demonstrate the four desired broadband functionalities while closely matching the design requirements, suggesting their potential in visible-range portable medical imaging devices. The findings of this work will open new horizons for active metasurface design with broadband complex multifunctionalities in different spectral bands.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Demodulation algorithm of low coherent heterodyne interference signal for axial clearance measurement of rotating machinery","authors":"Xing Fan, Yilin Ren, Peng Zhang, Xianming Liu, Xiaohua Lei, Weimin Chen","doi":"10.1016/j.optlastec.2024.111714","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111714","url":null,"abstract":"The time-domain low coherent heterodyne interference axial clearance measurement method has the challenges of small range and low precision in the clearance measurement of rotating machinery. An axial clearance demodulation algorithm based on the windowed power spectrum density transform (WPSD) is proposed. Based on the characteristics of low coherent heterodyne interference signal, the relationship model between window width and rotating structure motion parameters (amplitude of axial clearance change, rotor speed) is constructed, and the optimal window width mathematical model is obtained. The axial clearance measurement experiments are completed under different axial clearance measurement distances based on an experimental clearance platform, different rotor speeds and different axial clearance variation amplitudes. The experimental results show that the absolute error of the axial clearance reconstruction signal is less than 17 μm and the relative error is less than 4.8 % when the axial clearance measurement distance is 2.1 mm ∼ 11.3 mm, the rotor speed is in the range of 6000 rad/min ∼ 12000 rad/min, and the variation of axial clearance is in the range of 150 μm ∼ 350 μm. The experimental and simulation results are basically consistent.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-situ observation of CO gas bubble behavior in molten pool during direct laser deposition of WC-Co cermet material","authors":"Takuto Yamaguchi, Keigo Tanaka, Takeshi Suyama","doi":"10.1016/j.optlastec.2024.111561","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111561","url":null,"abstract":"Laser cladding of WC-Co cermet material is a promising means of improving the wear resistance of metal products. Layer-by-layer processing of laser cladding, also designated as laser directed energy deposition and laser metal deposition, is attracting attention as an alternative manufacturing process of cermet materials for conventional powder metallurgy processing. Laser cladding of WC-Co has constraints on its practical use because a clad bead of WC-Co often includes numerous defects such as cracks and pores. Various factors cause pores in clad beads. Therefore, establishing a method for restraining them is difficult. Obtaining dense clad beads having few pores requires the elucidation of behaviors of gas bubbles: the precursors of pores. Nevertheless, observations inside molten pools are difficult, thereby complicating the characterization of gas bubble behavior.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"148 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141933854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A filled-enhanced high-sensitivity optical fiber temperature sensor","authors":"Yin-song Zhao, Lu Cai, Jia-bao Xie, Gang Yang, Yong Zhao","doi":"10.1016/j.optlastec.2024.111543","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111543","url":null,"abstract":"In this paper, a temperature sensing structure comprising single-mode fiber (SMF) and dual-core single-side hole fiber (DCSHF) is introduced and demonstrated to enhance temperature sensing performance based on modal interference. The biased air hole of DCSHF minimizes temperature-induced variations in the effective refractive index of the core mode, resulting in high sensitivity of temperature sensing. For further enhancement, alcohol with a high thermo-optical coefficient is introduced into the air hole, while barium titanate microsphere is innovatively inserted as coupling factor to enhance mode coupling efficiency. The experimental results prove that the maximum sensitivity of this sensor can reach up to −5.57 nm/°C. The sensor offers advantages such as simple preparation, high sensitivity, excellent repeatability, rapid response, and remarkable stability, suggesting wide-ranging potential applications in temperature sensing.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141933855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hybrid laser welding and brazing for controlling intermetallic compounds in Al/Cu dissimilar joint","authors":"Weizhe Du, Xuting Huang, Min Zheng, Rongshi Xiao, Jiejie Xu, Ting Huang","doi":"10.1016/j.optlastec.2024.111559","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111559","url":null,"abstract":"Micro-welding of Al and Cu foils is increasing used in various industries, particularly in the production of battery components for electric vehicles. However, direct fusion welding of Al and Cu may compromise joint mechanical properties due to the formation of brittle intermetallic compounds (IMC). Consequently, strategies for controlling IMC to enhance joint mechanical properties have received significant research attention. In this study, lap welds of 1050 Al foil and T2 Cu foil (both 200 μm thick) are achieved using a single-mode fiber laser equipped with a scanning galvanometer. This setup enables spatial power modulation for laser spot welding via beam spiral scanning. Notably, laser fusion welding occurs along the laser beam scanning path, while laser weld-brazing is achieved through heat conduction in the spiral spacing between the adjacent scanning paths, resulting in a hybrid joint with alternated fused and brazed areas. The laser weld-brazing areas expand the effective connection area of the joint, improving its load-bearing capacity while effectively controlling IMC compared to fusion joints. The screw-type hybrid joints exhibit excellent mechanical properties, with a maximum tensile strength of 140 MPa. Experimental and simulation results indicate the mechanism for hybrid joint formation and improvement in mechanical properties. This study provides an effective strategy for regulating joint microstructure to mitigate the negative influence of IMC.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141933857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geometric calibration for photometric stereo under near-field point light sources using spheres","authors":"Jian Yu, Yuchong Chen, Feipeng Da","doi":"10.1016/j.optlastec.2024.111557","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111557","url":null,"abstract":"Spheres are commonly employed for both camera calibration and light calibration. The apparent contours of spheres are utilized to determine the camera’s intrinsic parameters, while the highlights on the sphere aid in estimating the light direction. This paper introduces a novel calibration method using spheres to simultaneously calibrate both the camera and light sources. The reflected irradiance distribution of the Lambertian sphere is analyzed under illumination from a near-field point light source. Consequently, points with the same luminance form coaxial circles. Their imaging equations are formulated under a general projection model, offering orthogonal constraints on the image of the absolute conic for fully calibrating the camera. Next, the geometric determination of the sphere centers and point light source positions is implemented. Finally, a photometric constraint is constructed to minimize the discrepancy between the synthetic and real images of the sphere, aiming to optimize the entire parameters of the system. The experiments are executed on synthetic and real datasets, with results indicating the effectiveness and precision of the proposed method.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141933923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Achieving zero efficiency droop in highly efficient N-polar AlGaN tunnel junction-based 254 nm DUV LED","authors":"Khalid Ayub, Banaras Khan, Yuhuai Liu, M. Nawaz Sharif, M. Ajmal Khan, Hideki Hirayama","doi":"10.1016/j.optlastec.2024.111567","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111567","url":null,"abstract":"The Minamata Convention of 2020 mandates the replacement of conventional mercury UV lamps with deep ultraviolet (DUV) light-emitting diodes (LEDs) emitting at 254 nm. But both the traditional DUV LEDs (C-LEDs) and tunnel junction (TJ)-based UVC LEDs face challenges such as high operating voltages and inefficient hole injection. Utilizing p-AlGaN and n-AlGaN layers-based TJ in DUV LEDs shows promise in addressing these issues, particularly in mitigating contact resistance and improving hole injection efficiency at the 254 nm emission wavelength. This study presents an approach to manipulate quantum tunnelling probability in n-AlGaN/p-AlGaN tunnel junctions by optimizing doping levels and thickness using APSYS Software simulations. The result is a suppression of Auger recombination and increased radiative recombination rates in 254 nm TJ-based DUV LEDs compared to C-LED. Theoretical modeling shows an internal quantum efficiency (IQE) of approximately 88 % with zero efficiency droop in TJ-based LEDs, a significant improvement over the approximately 66 % IQE with a 53 % efficiency droop in C-LEDs. This study reveals the highest theoretically possible IQE of 88 % at a 254 nm emission wavelength in TJ-based LED, with no efficiency droop. Moreover, TJ-LEDs show linear increases in light output powers (LOP) with varying current densities due to lower Auger recombination rates in their multi-quantum wells (MQWs). Notably, operating voltages reduce significantly from 21 V to 5.4 V under 200 A/cm operation, attributed to optimized TJ thickness and doping, along with a careful selection of lower Al-content in the contact layer. These findings pave the way for enhanced UV emitter growth using techniques like metal–organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE), promising advancements in biomedical applications.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"193 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141933861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MGRCFusion: An infrared and visible image fusion network based on multi-scale group residual convolution","authors":"Pan Zhu, Yufei Yin, Xinglin Zhou","doi":"10.1016/j.optlastec.2024.111576","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111576","url":null,"abstract":"The purpose of fusing infrared and visible images is to obtain an informative image that contains bright thermal targets and rich visible texture details. However, the existing deep learning-based algorithms generally neglect finer deep-level multi-scale features, and only the last layer of features is injected into the feature fusion strategy. To this end, we propose an optimized network model for deeper-level multi-scale features extraction based on multi-scale group residual convolution. Meanwhile, a dense connection module is designed to adequately integrate these multi-scale feature information. We contrast our method with advanced deep learning-based algorithms on multiple datasets. Extensive qualitative and quantitative experiments reveal that our method surpasses the existing fusion methods. Furthermore, ablation experiments illustrate the excellence of the multi-scale group residual convolution module for infrared and visible image fusion.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141933859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A microwave photonic mixer based on Stimulated Brillouin Scattering with high image rejection capacity","authors":"Wenqi Yu, Qianqian Jia, Guansu Xing, Jinye Li, Jianguo Liu, Canwen Zou","doi":"10.1016/j.optlastec.2024.111422","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111422","url":null,"abstract":"The electrical mixer is limited by operation bandwidth and parallel processing capacity, and is suffering from increasingly serious electro-magnetic interference. By introducing photonic properties, microwave photonic technology has many advantages compared to the traditional microwave technology, such as low loss, high bandwidth, high parallel processing capacity, anti-electromagnetic interference and so on. In this paper, a microwave photonic mixer based on Stimulated Brillouin Scattering (SBS) with high image rejection capacity is proposed. Due to the high wavelength-selectivity and wideband tunability of the SBS process, the image rejection ratio of the mixer exceeds 45 dB over the IF range of 0.1 GHz to 2 GHz and the RF range of 2 GHz to 40 GHz. The maximum of the image rejection ratio reaches 46.4 dB, at the same time, the conversion efficiency of the mixer is −28 dB.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141933926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Customizable dual-resonance sensing empowered by coupled quasi-bound states in the continuum","authors":"Xiao-Qing Luo, Yaojie Zhou, Qinke Liu, Zhendong Lu, Sha Chen, Yan Li, W.M. Liu","doi":"10.1016/j.optlastec.2024.111544","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111544","url":null,"abstract":"The quasi-bound states in the continuum (QBIC) have drawn increasing attention in optical metasurfaces derived from their ultrahigh quality factors, and show the utility to enhance the sensitivity of optical sensing. However, conventional single-resonance sensing may be inaccurate and unreliable, and then the dual-resonance sensing governed by the coupled QBIC is desired but remains elusive. Here, we show that the coupled QBIC modes can be leveraged to unfold dual-resonance refractive index sensing in the hybrid all-dielectric metasurface. Specifically, it is revealed that the toroidal dipole mode can be realized with strong electric field enhancement, enabling the implementation of anapole mode in the telecom short-wavelength band (1460–1530 nm). Under different linearly polarized illuminations, the dual symmetry-protected QBIC modes dominated by the electric quadrupole resonance can be fulfilled in the telecom extended-wavelength band (1360–1460 nm). Within this framework, the polarization-dependent dual symmetry-protected QBIC modes selectively coupled with the toroidal dipole mode or the anapole mode can not only uncover the transformation from Fano resonance to analog of electromagnetically induced transparency, but also manifest two types of high-sensitivity dual-resonance refractive index sensing in the telecom extended-wavelength and short-wavelength bands. The dual-resonance refractive index sensing can also be extended to telecom long-wavelength band (1565–1625 nm) and ultra-long-wavelength band (1625–1675 nm) with enhanced sensitivity. These results offer exploration potential for multi-channel sensing, optical modulators, and slow-light devices.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141933930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}