Pub Date : 2025-03-19DOI: 10.1016/j.optlastec.2025.112793
Naveen Kumar Maurya , Sadhana Kumari , G. Challa Ram , Sumithra P.
A tunable triband metasurface absorber (TTMSA) based on interconnected octagonal concentric graphene rings (OCGRs) has been proposed. The effective capacitance between the OCGRs has been optimized to achieve near-unity absorptivity () at 2.89, 4.38, and 6.33 THz by adjusting the position of the middle graphene ring. The simplicity of unit cell design enables the possible fabrication of TTMSAs through semiconductor fabrication technology. The symmetricity in the design leads to the polarization-insensitivity. Meanwhile, TTMSA shows angular stability for incidence angle () 60° with 90% under both transverse electric and magnetic polarizations. The TTMSA provides excellent frequency tunability at all three bands. The variation in from 0.3 to 1 eV leads to the frequency sweep from 2.23 to 8.9 THz, corresponding to 119.86% fractional bandwidth. The developed circuit model follows the results obtained from the simulations. The TTMSA is highly compact and ultra-thin, having periodicity and thickness of /12.98 and /51.91, respectively, making it suitable for size-constrained THz applications. The excitation of multiple plasmonic modes based on the surface plasmon polariton (SPP) resonance makes TTMSA a THz plasmonic device.
{"title":"Tunable triband graphene metasurface absorber with wide frequency agility for 6G and beyond communication in THz gap regime","authors":"Naveen Kumar Maurya , Sadhana Kumari , G. Challa Ram , Sumithra P.","doi":"10.1016/j.optlastec.2025.112793","DOIUrl":"10.1016/j.optlastec.2025.112793","url":null,"abstract":"<div><div>A tunable triband metasurface absorber (TTMSA) based on interconnected octagonal concentric graphene rings (OCGRs) has been proposed. The effective capacitance between the OCGRs has been optimized to achieve near-unity absorptivity (<span><math><mrow><mi>A</mi><mrow><mo>(</mo><mi>f</mi><mo>)</mo></mrow></mrow></math></span>) at 2.89, 4.38, and 6.33 THz by adjusting the position of the middle graphene ring. The simplicity of unit cell design enables the possible fabrication of TTMSAs through semiconductor fabrication technology. The symmetricity in the design leads to the polarization-insensitivity. Meanwhile, TTMSA shows angular stability for incidence angle (<span><math><mi>θ</mi></math></span>) <span><math><mo>≤</mo></math></span> 60° with <span><math><mrow><mi>A</mi><mrow><mo>(</mo><mi>f</mi><mo>)</mo></mrow></mrow></math></span> <span><math><mo>≥</mo></math></span> 90% under both transverse electric and magnetic polarizations. The TTMSA provides excellent frequency tunability at all three bands. The variation in <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> from 0.3 to 1 eV leads to the frequency sweep from 2.23 to 8.9 THz, corresponding to 119.86% fractional bandwidth. The developed circuit model follows the results obtained from the simulations. The TTMSA is highly compact and ultra-thin, having periodicity and thickness of <span><math><msub><mrow><mi>λ</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>/12.98 and <span><math><msub><mrow><mi>λ</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>/51.91, respectively, making it suitable for size-constrained THz applications. The excitation of multiple plasmonic modes based on the surface plasmon polariton (SPP) resonance makes TTMSA a THz plasmonic device.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"187 ","pages":"Article 112793"},"PeriodicalIF":4.6,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-19DOI: 10.1016/j.optlastec.2025.112810
Rong Zhao, Xinda Lu, Chenhui Gao, Xinyu Ye, Hao Li, Baiyi Wu, Meng Wang, Zefeng Wang
A highly localized fiber Bragg grating (FBG) fabrication method has been proposed. The method utilizes the principle of introducing spherical aberration by a quartz glass plate to achieve a uniform filamentary modulation region induced by a single femtosecond laser pulse in a single-mode fiber. The focusing spot of the femtosecond laser passing through quartz glass plates with different thicknesses has been simulated. Combined with the results of femtosecond laser single-pulse fabrication, the effect of spherical aberration introduced by the quartz glass plate on the filament morphology has been analyzed. Based on this method, highly localized FBG arrays have been inscribed using the femtosecond laser point-by-point inscription technology. When the periods of the FBG arrays are the same, this method can effectively improve the reflectivity of FBGs without increasing the insertion loss. The method of modulating the filament morphology by adjusting the thickness of the glass plate offers a more efficient means for the fabrication of FBGs, and the high-integration FBG arrays have extensive application prospects in sensing and communication.
{"title":"Highly localized FBG fabricated by femtosecond laser single-pulse filaments","authors":"Rong Zhao, Xinda Lu, Chenhui Gao, Xinyu Ye, Hao Li, Baiyi Wu, Meng Wang, Zefeng Wang","doi":"10.1016/j.optlastec.2025.112810","DOIUrl":"10.1016/j.optlastec.2025.112810","url":null,"abstract":"<div><div>A highly localized fiber Bragg grating (FBG) fabrication method has been proposed. The method utilizes the principle of introducing spherical aberration by a quartz glass plate to achieve a uniform filamentary modulation region induced by a single femtosecond laser pulse in a single-mode fiber. The focusing spot of the femtosecond laser passing through quartz glass plates with different thicknesses has been simulated. Combined with the results of femtosecond laser single-pulse fabrication, the effect of spherical aberration introduced by the quartz glass plate on the filament morphology has been analyzed. Based on this method, highly localized FBG arrays have been inscribed using the femtosecond laser point-by-point inscription technology. When the periods of the FBG arrays are the same, this method can effectively improve the reflectivity of FBGs without increasing the insertion loss. The method of modulating the filament morphology by adjusting the thickness of the glass plate offers a more efficient means for the fabrication of FBGs, and the high-integration FBG arrays have extensive application prospects in sensing and communication.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"187 ","pages":"Article 112810"},"PeriodicalIF":4.6,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.optlastec.2025.112808
Mai M. Khalaf , Mohamed Gouda , Manal F. Abou Taleb , Haifa S. Al Ghamdi , Hany M. Abd El-Lateef
The ongoing search for materials with desirable properties aligns with the demands of rapid technological advancement, while also prioritizing cost-effectiveness in both material selection and preparation. Therefore, one of the cheapest copper complexes was chosen, which istetraaminecopper (II) sulfate monohydrate. Copper complex thin films were fabricated using spin coating, one of the simplest and most cost-effective methods.The molecular and crystalline structure properties of the prepared films were analyzed and compared to those of their powdered counterparts. Topography analysis via field emission scanning electron microscopy (FE-SEM) showed that the films were composed of nanoplatelets with an average thickness of 50 nm.The optical properties of the prepared films were also examined, using a spectrophotometer focusing on absorption spectra and band gap energy determination.The strong absorption properties are observed in the UV–vis-NIR spectra with a direct energy gap of approximately 2.83 eV.The electrical properties of the copper complex film deposited on p-type silicon were examined under both dark and illuminated conditions to evaluate its potential for photosensing applications. The fabricated heterojunction demonstrated notable sensitivity to changes in the incident illumination power density, with a high photocurrent density of 0.02 A/cm2.Additionally, key photosensing parameters including photoresponsivity, specific detectivity, linear dynamic range, and response speed based on rise and fall times were calculated. The fabricated device demonstrated excellent performance, achieving a responsivity of 237.8 mA/W and the capability to detect weak light signals with a specific detectivity of 4.17 × 109 cm·Hz1/2/W. It also exhibited a linear dynamic range of 13.24 dB and fast response times, with rise and fall times of 38 ms and 226 ms, respectively.A comparison of the performance parameters of the currently prepared device with those from previously published junctions reveals its clear superiority, making it well-suited for photosensor applications.
{"title":"Fabrication, characterization of the optical and photosensing properties of copper complex nanoplatelets thin films","authors":"Mai M. Khalaf , Mohamed Gouda , Manal F. Abou Taleb , Haifa S. Al Ghamdi , Hany M. Abd El-Lateef","doi":"10.1016/j.optlastec.2025.112808","DOIUrl":"10.1016/j.optlastec.2025.112808","url":null,"abstract":"<div><div>The ongoing search for materials with desirable properties aligns with the demands of rapid technological advancement, while also prioritizing cost-effectiveness in both material selection and preparation. Therefore, one of the cheapest copper complexes was chosen, which istetraaminecopper (II) sulfate monohydrate. Copper complex thin films were fabricated using spin coating, one of the simplest and most cost-effective methods.The molecular and crystalline structure properties of the prepared films were analyzed and compared to those of their powdered counterparts. Topography analysis via field emission scanning electron microscopy (FE-SEM) showed that the films were composed of nanoplatelets with an average thickness of 50 nm.The optical properties of the prepared films were also examined, using a<!--> <!-->spectrophotometer focusing on absorption spectra and band gap energy determination.The strong absorption properties are observed in the UV–vis-NIR spectra with a direct energy gap of approximately 2.83 eV.The electrical properties of the copper complex film deposited on p-type silicon were examined under both dark and illuminated conditions to evaluate its potential for photosensing applications. The fabricated heterojunction demonstrated notable sensitivity to changes in the incident illumination power density, with a high photocurrent density of 0.02 A/cm<sup>2</sup>.Additionally, key photosensing parameters including photoresponsivity, specific detectivity, linear dynamic range, and response speed based on rise and fall times were calculated. The fabricated device demonstrated excellent performance, achieving a responsivity of 237.8 mA/W and the capability to detect weak light signals with a specific detectivity of 4.17 × 10<sup>9</sup> cm·Hz<sup>1/2</sup>/W. It also exhibited a linear dynamic range of 13.24 dB and fast response times, with rise and fall times of 38 ms and 226 ms, respectively.A comparison of the performance parameters of the currently prepared device with those from previously published junctions reveals its clear superiority, making it well-suited for photosensor applications.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"187 ","pages":"Article 112808"},"PeriodicalIF":4.6,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.optlastec.2025.112820
Longyuan Yu , Huachao Cheng , Feng Liu , Peng Li , Sheng Liu , Xuetao Gan , Jianlin Zhao
In this work, a novel surface periodic nanostructure generation methodology employing shaped circularly polarized femtosecond laser beam was introduced. The orientation of the periodic nanostructure exhibits strong dependence on the beam shape instead of the polarization state of incident laser. In experiments, focused circularly polarized femtosecond laser beams with line-shaped cross section were utilized to normally irradiate the surface of semiconductor or metal, and periodic ripples were generated within the ablation zones. The thresholds for laser pulse energy, pulse number, and beam width of incident laser for ripples generation were investigated. Furthermore, the generation of periodic nanostructures with varying orientations was demonstrated using shaped laser beam with multi- and single-exposure strategies. Our findings suggest a potential means to relax the necessity for high linear polarization in the formation of periodic surface nanostructures.
{"title":"Beam-shape-dependent periodic surface nanostructure using circularly polarized femtosecond laser","authors":"Longyuan Yu , Huachao Cheng , Feng Liu , Peng Li , Sheng Liu , Xuetao Gan , Jianlin Zhao","doi":"10.1016/j.optlastec.2025.112820","DOIUrl":"10.1016/j.optlastec.2025.112820","url":null,"abstract":"<div><div>In this work, a novel surface periodic nanostructure generation methodology employing shaped circularly polarized femtosecond laser beam was introduced. The orientation of the periodic nanostructure exhibits strong dependence on the beam shape instead of the polarization state of incident laser. In experiments, focused circularly polarized femtosecond laser beams with line-shaped cross section were utilized to normally irradiate the surface of semiconductor or metal, and periodic ripples were generated within the ablation zones. The thresholds for laser pulse energy, pulse number, and beam width of incident laser for ripples generation were investigated. Furthermore, the generation of periodic nanostructures with varying orientations was demonstrated using shaped laser beam with multi- and single-exposure strategies. Our findings suggest a potential means to relax the necessity for high linear polarization in the formation of periodic surface nanostructures.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"187 ","pages":"Article 112820"},"PeriodicalIF":4.6,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.optlastec.2025.112801
Xiaoyun Sun , Wenjun Wang , Xuesong Mei , Chuanwei Zhang , Feiyan Han , Peng Zhang
This study investigates the preparation and recognition of marking patterns on high-temperature-resistant polyimide (PI) film surfaces using femtosecond laser. By optimizing laser processing parameters, PI surfaces with anti-reflective micro/nano structures and diffractive laser-induced periodic surface structures (LIPSSs) were obtained. Moreover, the traditional two-dimensional code and color code were fabricated based on the optimal laser processing parameters. Subsequently, after laser processing, Raman spectroscopy indicated carbonization on the PI surface. An analysis of the atomic ratios and group content on the PI surface revealed that the alteration of chemical groups was dependent on the generation and removal processes. High-temperature testing demonstrated that the marking patterns on the PI surface remained stable in environments up to 300 ℃, with no significant changes observed in the traditional two-dimensional code after exposure to high temperatures. The color code comprised four colors: the inherent brown-yellow of the PI substrate, black from ablation, and two additional colors induced during processing. Furthermore, the color code was recognized by separately extracting the black, yellow, and purple parts. Therefore, this research further achieved the marking patterns with easy identification, high capacity, and high-temperature resistance on PI film.
{"title":"High-temperature resistant marking patterns prepared on polyimide film using femtosecond laser","authors":"Xiaoyun Sun , Wenjun Wang , Xuesong Mei , Chuanwei Zhang , Feiyan Han , Peng Zhang","doi":"10.1016/j.optlastec.2025.112801","DOIUrl":"10.1016/j.optlastec.2025.112801","url":null,"abstract":"<div><div>This study investigates the preparation and recognition of marking patterns on high-temperature-resistant polyimide (PI) film surfaces using femtosecond laser. By optimizing laser processing parameters, PI surfaces with anti-reflective micro/nano structures and diffractive laser-induced periodic surface structures (LIPSSs) were obtained. Moreover, the traditional two-dimensional code and color code were fabricated based on the optimal laser processing parameters. Subsequently, after laser processing, Raman spectroscopy indicated carbonization on the PI surface. An analysis of the atomic ratios and group content on the PI surface revealed that the alteration of chemical groups was dependent on the generation and removal processes. High-temperature testing demonstrated that the marking patterns on the PI surface remained stable in environments up to 300 ℃, with no significant changes observed in the traditional two-dimensional code after exposure to high temperatures. The color code comprised four colors: the inherent brown-yellow of the PI substrate, black from ablation, and two additional colors induced during processing. Furthermore, the color code was recognized by separately extracting the black, yellow, and purple parts. Therefore, this research further achieved the marking patterns with easy identification, high capacity, and high-temperature resistance on PI film.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"187 ","pages":"Article 112801"},"PeriodicalIF":4.6,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.optlastec.2025.112643
Xi Wang , Hang Yuan , ZhenXiong Jian , Duo Li , XinQuan Zhang , LiMin Zhu , MingJun Ren
Machined metal surfaces exhibit non-Lambertian reflectance with complex highlight that dramatically undermines the performance of three-dimensional optical measurement methods. To address this problem, this study proposes a neural measurement method based on near-field photometric stereo to obtain accurate measurements of machined metal surfaces. A tangent estimation network is designed to enable the photometric stereo to suppress the effect of the anisotropic metal reflectance on the surface normal estimation. In addition, a projector is introduced into the photometric stereo system to output an initial point cloud that helps the network adapt to near-field scenes and rectify the error accumulation of normal integration. Synthetic experiments based on public anisotropic reflectance data demonstrate that the proposed photometric stereo network with tangent estimation improves the surface normal estimation accuracy of anisotropic metal reflectance surfaces. Real experiments based on eight machined metal surfaces demonstrate that the proposed neural measurement method obtains a measurement accuracy of 59 um compared with the measurement results of the coordinate measurement machines.
{"title":"Neural measurement method based on near-field photometric stereo with tangent estimation for machined metal surfaces","authors":"Xi Wang , Hang Yuan , ZhenXiong Jian , Duo Li , XinQuan Zhang , LiMin Zhu , MingJun Ren","doi":"10.1016/j.optlastec.2025.112643","DOIUrl":"10.1016/j.optlastec.2025.112643","url":null,"abstract":"<div><div>Machined metal surfaces exhibit non-Lambertian reflectance with complex highlight that dramatically undermines the performance of three-dimensional optical measurement methods. To address this problem, this study proposes a neural measurement method based on near-field photometric stereo to obtain accurate measurements of machined metal surfaces. A tangent estimation network is designed to enable the photometric stereo to suppress the effect of the anisotropic metal reflectance on the surface normal estimation. In addition, a projector is introduced into the photometric stereo system to output an initial point cloud that helps the network adapt to near-field scenes and rectify the error accumulation of normal integration. Synthetic experiments based on public anisotropic reflectance data demonstrate that the proposed photometric stereo network with tangent estimation improves the surface normal estimation accuracy of anisotropic metal reflectance surfaces. Real experiments based on eight machined metal surfaces demonstrate that the proposed neural measurement method obtains a measurement accuracy of 59 um compared with the measurement results of the coordinate measurement machines.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"187 ","pages":"Article 112643"},"PeriodicalIF":4.6,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.optlastec.2025.112829
Wei Zan , Qing Bai , Xinyi Liu , Mingyuan Yang , Yu Wang , Baoquan Jin
A nonuniform probe compensation method is proposed for gain spectrum calibration in the distributed Brillouin optical time-domain analyzer (BOTDA). Pseudo-random distributed power fluctuations are quantified by determining the slow-changing component from the Lorentzian fitting residuals of the raw gain spectrum and compensated. Experimental results indicate that the normalized Brillouin gain uncertainty is suppressed from 10.08 % to 0.24 %. The fitting coefficient between the ΔBFS and temperature variation is improved to 0.9999, with the average fitting residual decreasing from 3.41 MHz to 0.27 MHz. The research demonstrates that the method effectively mitigates the impact of optical power instability, significantly improving BFS accuracy in BOTDA.
{"title":"Reducing the impact of optical power fluctuations in BOTDA using nonuniform probe compensation methods","authors":"Wei Zan , Qing Bai , Xinyi Liu , Mingyuan Yang , Yu Wang , Baoquan Jin","doi":"10.1016/j.optlastec.2025.112829","DOIUrl":"10.1016/j.optlastec.2025.112829","url":null,"abstract":"<div><div>A nonuniform probe compensation method is proposed for gain spectrum calibration in the distributed Brillouin optical time-domain analyzer (BOTDA). Pseudo-random distributed power fluctuations are quantified by determining the slow-changing component from the Lorentzian fitting residuals of the raw gain spectrum and compensated. Experimental results indicate that the normalized Brillouin gain uncertainty is suppressed from 10.08 % to 0.24 %. The fitting coefficient between the Δ<sub>BFS</sub> and temperature variation is improved to 0.9999, with the average fitting residual decreasing from 3.41 <!--> <!-->MHz to 0.27 <!--> <!-->MHz. The research demonstrates that the method effectively mitigates the impact of optical power instability, significantly improving BFS accuracy in BOTDA.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"187 ","pages":"Article 112829"},"PeriodicalIF":4.6,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.optlastec.2025.112727
Fannuo Xu , Zhiping Wang , Zipei Wu , An Pan
Quantitative phase imaging (QPI) is gaining significant recognition in the field of biological imaging due to its ability to accurately and non-invasively retrieve phase shifts within samples. Fourier ptychographic microscopy (FPM) is a high-resolution imaging technology commonly employed for QPI because of its capability to capture a vast field of view and recover phase information. Typically, FPM requires an initial image with a high signal-to-noise ratio. To address its theoretical constraints, the image is often divided into blocks for processing. This letter presents the implementation of a quantitative phase imaging method based on the recently introduced feature-domain Fourier ptychographic technique. The proposed method is designed to be robust against noise and eliminates the need for binning the original image. Compared with conventional methods, our approach demonstrates high performance and flexible recovery results in both simulations and experiments.
{"title":"Wide-field quantitative phase imaging without slicing via feature-domain Fourier ptychographic microscopy","authors":"Fannuo Xu , Zhiping Wang , Zipei Wu , An Pan","doi":"10.1016/j.optlastec.2025.112727","DOIUrl":"10.1016/j.optlastec.2025.112727","url":null,"abstract":"<div><div>Quantitative phase imaging (QPI) is gaining significant recognition in the field of biological imaging due to its ability to accurately and non-invasively retrieve phase shifts within samples. Fourier ptychographic microscopy (FPM) is a high-resolution imaging technology commonly employed for QPI because of its capability to capture a vast field of view and recover phase information. Typically, FPM requires an initial image with a high signal-to-noise ratio. To address its theoretical constraints, the image is often divided into blocks for processing. This letter presents the implementation of a quantitative phase imaging method based on the recently introduced feature-domain Fourier ptychographic technique. The proposed method is designed to be robust against noise and eliminates the need for binning the original image. Compared with conventional methods, our approach demonstrates high performance and flexible recovery results in both simulations and experiments.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"187 ","pages":"Article 112727"},"PeriodicalIF":4.6,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-17DOI: 10.1016/j.optlastec.2025.112735
Yue Qiu , Leshi Shu , Minjie Song , Shaoning Geng , Yilin Wang , Di Wu , Deyuan Ma
High-power laser-MAG hybrid welding (HPLMHW) offers good penetration and bridging ability for medium-thick plates. However, the instability of intense interaction between the dual heat sources and the weldment causes defects like root humping, with inadequately understood mechanisms and insufficient monitoring of defect types. Additionally, in HPLMHW monitoring, similarities among defects and intense periodic interference make it difficult to monitor accurately and adjust subsequent welding parameters. To address these issues, this research studies and defines the formations and types of root humping in HPLMHW, and proposes an improved transformer-based network for real-time monitoring of five weld types including diverse root humping defects. Firstly, the formation mechanism of diverse root humping in HPLMHW is revealed and diverse categories of root humping are defined. Next, using the established top-view monitoring platform, a dataset of five weld types including distinct root humping is constructed, differing from other welding monitoring studies. Then, the research proposed an enhanced convolutional transformer network for real-time defect monitoring in the mentioned HPLMHW process environment with intense noise interference, periodic objects overlap, and similar top-view formation processes of multi defects, named Sparse and Multi Attention Convolution Transformer Network (SMACTnet). SMACTnet combines sparse and multiple attention mechanisms within Transformer and CNN frameworks. It leverages the advantages of Transformers for global feature extraction and CNNs for local feature extraction, enhances defect class features, minimizes noise and periodic overlap interference, and improves monitoring accuracy. Comparison experiments on a test set of new welds demonstrate that the SMACTnet outperforms other models in overall performance and effectively monitors welds, including incomplete penetration, two types of root humping, surface collapse and well-formed.
{"title":"Real-time defect monitoring in high-power laser-MAG hybrid welding with an improved multi attention mechanisms convolution transformer network","authors":"Yue Qiu , Leshi Shu , Minjie Song , Shaoning Geng , Yilin Wang , Di Wu , Deyuan Ma","doi":"10.1016/j.optlastec.2025.112735","DOIUrl":"10.1016/j.optlastec.2025.112735","url":null,"abstract":"<div><div>High-power laser-MAG hybrid welding (HPLMHW) offers good penetration and bridging ability for medium-thick plates. However, the instability of intense interaction between the dual heat sources and the weldment causes defects like root humping, with inadequately understood mechanisms and insufficient monitoring of defect types. Additionally, in HPLMHW monitoring, similarities among defects and intense periodic interference make it difficult to monitor accurately and adjust subsequent welding parameters. To address these issues, this research studies and defines the formations and types of root humping in HPLMHW, and proposes an improved transformer-based network for real-time monitoring of five weld types including diverse root humping defects. Firstly, the formation mechanism of diverse root humping in HPLMHW is revealed and diverse categories of root humping are defined. Next, using the established top-view monitoring platform, a dataset of five weld types including distinct root humping is constructed, differing from other welding monitoring studies. Then, the research proposed an enhanced convolutional transformer network for real-time defect monitoring in the mentioned HPLMHW process environment with intense noise interference, periodic objects overlap, and similar top-view formation processes of multi defects, named Sparse and Multi Attention Convolution Transformer Network (SMACTnet). SMACTnet combines sparse and multiple attention mechanisms within Transformer and CNN frameworks. It leverages the advantages of Transformers for global feature extraction and CNNs for local feature extraction, enhances defect class features, minimizes noise and periodic overlap interference, and improves monitoring accuracy. Comparison experiments on a test set of new welds demonstrate that the SMACTnet outperforms other models in overall performance and effectively monitors welds, including incomplete penetration, two types of root humping, surface collapse and well-formed.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"187 ","pages":"Article 112735"},"PeriodicalIF":4.6,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Total internal reflectance depends on the ratio of refractive indexes on each side of the interface. Enhancement of its angular range is challenging in YAG laser systems due to the low index of gain material. Therefore, we propose the nanoengineered multilayer stack of silica material formed by glancing angle deposition technique. Each layer of silica has lower refractive index material compared with YAG and it allows to reach total internal reflectance at the angles down to 46 degrees. Such coating design is also over-coated with dense multilayer which allows to connect it to the cooling system and gain favorable spectral performance at different angles.
{"title":"Enhancement of total internal reflection in Nd:YAG crystals by multilayer nanostructured coatings","authors":"Lukas Ramalis , Simas Melnikas , Deividas Buinovskis , Tomas Tolenis","doi":"10.1016/j.optlastec.2025.112807","DOIUrl":"10.1016/j.optlastec.2025.112807","url":null,"abstract":"<div><div>Total internal reflectance depends on the ratio of refractive indexes on each side of the interface. Enhancement of its angular range is challenging in YAG laser systems due to the low index of gain material. Therefore, we propose the nanoengineered multilayer stack of silica material formed by glancing angle deposition technique. Each layer of silica has lower refractive index material compared with YAG and it allows to reach total internal reflectance at the angles down to 46 degrees. Such coating design is also over-coated with dense multilayer which allows to connect it to the cooling system and gain favorable spectral performance at different angles.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"187 ","pages":"Article 112807"},"PeriodicalIF":4.6,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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