Pub Date : 2026-05-01Epub Date: 2026-01-31DOI: 10.1016/j.optlastec.2026.114833
Jihongbo Shen , Heng Yuan , Hongyu Tao , Zekun Niu , Haoming Xu , Chentao Zhang , Chen Su , Zhuo Wang , Chen Zhang
Magnetometry based on diamond nitrogen-vacancy (NV) centers has been extensively studied for applications requiring diverse capabilities, spanning from nanometer spatial resolution to subpicotesla sensitivity. Among various applications, diamond magnetometers can demonstrate high sensitivity magnetic sensing within millimeter-scale size for endoscopic applications. However, the trade-off between sensitivity and spatial resolution of diamond magnetometry makes it difficult to achieve such a probe. In this study, we present a millimeter-scale rigid diamond magnetometer probe with enhanced sensitivity via optimizing the optical design. By coupling the frustum diamond with the miniaturized compound parabolic concentrator (CPC) lens, we enhance the fluorescence collection efficiency by 37% within 4 mm diameter, and the achieved sensitivity is 200pT/Hz1/2 based on the sample with the resonance linewidth of ∼ 8 MHz. With this verified structure, endoscopes with mm-size probe and picotesla sensitivity can be projected for surgical and industrial applications in the future.
{"title":"Millimeter-scale rigid diamond probe for high sensitivity endoscopic-magnetometry applications","authors":"Jihongbo Shen , Heng Yuan , Hongyu Tao , Zekun Niu , Haoming Xu , Chentao Zhang , Chen Su , Zhuo Wang , Chen Zhang","doi":"10.1016/j.optlastec.2026.114833","DOIUrl":"10.1016/j.optlastec.2026.114833","url":null,"abstract":"<div><div>Magnetometry based on diamond nitrogen-vacancy (NV) centers has been extensively studied for applications requiring diverse capabilities, spanning from nanometer spatial resolution to subpicotesla sensitivity. Among various applications, diamond magnetometers can demonstrate high sensitivity magnetic sensing within millimeter-scale size for endoscopic applications. However, the trade-off between sensitivity and spatial resolution of diamond magnetometry makes it difficult to achieve such a probe. In this study, we present a millimeter-scale rigid diamond magnetometer probe with enhanced sensitivity via optimizing the optical design. By coupling the frustum diamond with the miniaturized compound parabolic concentrator (CPC) lens, we enhance the fluorescence collection efficiency by 37% within 4 mm diameter, and the achieved sensitivity is 200pT/Hz<sup>1/2</sup> based on the sample with the resonance linewidth of ∼ 8 MHz. With this verified structure, endoscopes with mm-size probe and picotesla sensitivity can be projected for surgical and industrial applications in the future.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114833"},"PeriodicalIF":5.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189902","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 : 2026-05-01Epub Date: 2026-01-28DOI: 10.1016/j.optlastec.2026.114826
Ruiji Dong , Jun-an Li , Fang-Jie Shu , Qijing Lu
Optical frequency combs (OFCs) based on microresonators with whispering-gallery modes offer several advantages, such as compact size, low power consumption, and simplified generation systems. These characteristics make OFCs highly suitable for applications in optical communications, bioimaging, and optical sensing. However, in small microsphere resonators (< 150 μm) operating in the C-band, the inherent geometric normal dispersion cannot be effectively compensated by material dispersion, thereby hindering OFC generation. In this study, we numerically investigated a silica microsphere resonator coated with a low-refractive-index thin film and calculated the dispersion characteristics of the first two radial modes across varying film thicknesses. The simulations demonstrate that by adjusting the film thickness from 0 to 1.2 μm, the zero-dispersion wavelength can be blue-shifted by up to 600 nm, and the group velocity dispersion curve can be effectively flattened. This allows for precise dispersion engineering of the microsphere, enabling anomalous dispersion over a broad wavelength range. Experimentally, we fabricated a 120 μm-diameter silica microsphere resonator coated with a ZrO2-SiO2 thin film via the sol–gel method, achieving an anomalous dispersion window. A broadband OFC with a spectral span exceeding 400 nm was generated using a single 1550 nm pump laser. The experimental results closely matched the simulations, validating the proposed approach. This work addresses the key challenge of dispersion control in miniaturized microsphere resonators and establishes a viable strategy for realizing chip-integrated frequency combs in the communication band.
{"title":"Dispersion engineering in Sol-Gel coated silica Microspheres: From normal to anomalous dispersion for broadband Kerr frequency comb generation","authors":"Ruiji Dong , Jun-an Li , Fang-Jie Shu , Qijing Lu","doi":"10.1016/j.optlastec.2026.114826","DOIUrl":"10.1016/j.optlastec.2026.114826","url":null,"abstract":"<div><div>Optical frequency combs (OFCs) based on microresonators with whispering-gallery modes offer several advantages, such as compact size, low power consumption, and simplified generation systems. These characteristics make OFCs highly suitable for applications in optical communications, bioimaging, and optical sensing. However, in small microsphere resonators (< 150 μm) operating in the C-band, the inherent geometric normal dispersion cannot be effectively compensated by material dispersion, thereby hindering OFC generation. In this study, we numerically investigated a silica microsphere resonator coated with a low-refractive-index thin film and calculated the dispersion characteristics of the first two radial modes across varying film thicknesses. The simulations demonstrate that by adjusting the film thickness from 0 to 1.2 μm, the zero-dispersion wavelength can be blue-shifted by up to 600 nm, and the group velocity dispersion curve can be effectively flattened. This allows for precise dispersion engineering of the microsphere, enabling anomalous dispersion over a broad wavelength range. Experimentally, we fabricated a 120 μm-diameter silica microsphere resonator coated with a ZrO<sub>2</sub>-SiO<sub>2</sub> thin film via the sol–gel method, achieving an anomalous dispersion window. A broadband OFC with a spectral span exceeding 400 nm was generated using a single 1550 nm pump laser. The experimental results closely matched the simulations, validating the proposed approach. This work addresses the key challenge of dispersion control in miniaturized microsphere resonators and establishes a viable strategy for realizing chip-integrated frequency combs in the communication band.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114826"},"PeriodicalIF":5.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079571","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 : 2026-05-01Epub Date: 2026-01-29DOI: 10.1016/j.optlastec.2026.114837
Tao Wang , Yufan Xie , Xinling Song , Guang Yang , Peipei Sun
To address the critical issues of coarse columnar grains, porosity, and Laves phase precipitation caused by rapid solidification in laser melting deposition (LMD) of Inconel 625 (IN625) nickel-based superalloy, this study systematically investigates the influence of annular oscillating laser deposition on the microstructure regulation mechanism and forming quality. By establishing a three-dimensional thermal-fluid coupling numerical model combined with single-track deposition experiments, the synergistic mechanism of laser power and scanning speed on the thermo-fluid behavior of the molten pool and solidification structure was revealed. The results indicate that at a laser power of 1200 W and a scanning speed of 15 mm/s, the Marangoni convection intensity inside the molten pool is moderate (peak flow velocity of 0.61 m/s), and the ratio of temperature gradient to cooling rate (G/R) significantly decreases to 4.32 × 10^4 K·s/m2, effectively promoting the transition from columnar to equiaxed crystals. The proportion of equiaxed crystals increases by more than 30%, and the average grain size is refined to 66.5 μm. The combined effects of thermal field homogenization and molten pool stirring induced by annular oscillation are identified as the main reasons for microstructure refinement and defect inhibition. However, excessive heat input (≥1800 W) induces turbulence and spattering, while an excessively high scanning speed (≥18 mm/s) leads to microstructural coarsening and disorder. This study aims to provide a key process window and theoretical basis for high-performance IN625 additive manufacturing.
{"title":"Optimization of process parameters for annular oscillating laser deposited IN625: A numerical and experimental study","authors":"Tao Wang , Yufan Xie , Xinling Song , Guang Yang , Peipei Sun","doi":"10.1016/j.optlastec.2026.114837","DOIUrl":"10.1016/j.optlastec.2026.114837","url":null,"abstract":"<div><div>To address the critical issues of coarse columnar grains, porosity, and Laves phase precipitation caused by rapid solidification in laser melting deposition (LMD) of Inconel 625 (IN625) nickel-based superalloy, this study systematically investigates the influence of annular oscillating laser deposition on the microstructure regulation mechanism and forming quality. By establishing a three-dimensional thermal-fluid coupling numerical model combined with single-track deposition experiments, the synergistic mechanism of laser power and scanning speed on the thermo-fluid behavior of the molten pool and solidification structure was revealed. The results indicate that at a laser power of 1200 W and a scanning speed of 15 mm/s, the Marangoni convection intensity inside the molten pool is moderate (peak flow velocity of 0.61 m/s), and the ratio of temperature gradient to cooling rate (G/R) significantly decreases to 4.32 × 10^4 K·s/m<sup>2</sup>, effectively promoting the transition from columnar to equiaxed crystals. The proportion of equiaxed crystals increases by more than 30%, and the average grain size is refined to 66.5 μm. The combined effects of thermal field homogenization and molten pool stirring induced by annular oscillation are identified as the main reasons for microstructure refinement and defect inhibition. However, excessive heat input (≥1800 W) induces turbulence and spattering, while an excessively high scanning speed (≥18 mm/s) leads to microstructural coarsening and disorder. This study aims to provide a key process window and theoretical basis for high-performance IN625 additive manufacturing.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114837"},"PeriodicalIF":5.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079563","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 : 2026-05-01Epub Date: 2026-01-31DOI: 10.1016/j.optlastec.2026.114839
Zichao Liu , Wanhong Wen , Yingbin Li , Benhai Yu , Cheng Huang
We theoretically study the two-photon ionization of H for the laser frequency range (0.25, 0.5) a.u. by numerically solving the time-dependent Schrödinger equation. The results show that the photoelectron angular distributions (PADs) are strongly dependent on the laser frequency. In the vicinity of the resonant frequency, the photoelectron momentum distributions show a doublet structure. For the inner ring, the population in the parallel direction is larger than the perpendicular direction, and the distribution shows little variation with the laser frequency. For the outer ring, as the laser frequency increases, the electron emissions transfer from the parallel to perpendicular direction. Below the resonant frequency region, the proportion of the perpendicular emissions increases with the laser frequency decreasing. Above the resonant frequency region, the electron emissions transfer from the perpendicular to parallel direction, and finally the dominant emission direction becomes the parallel direction. By separating the contributions from the outgoing s wave, d wave and their interference, the strong dependency of the PADs on the laser frequency can be well understood. These results provide deep insights into the two-photon ionization by ultraviolet laser pulses.
{"title":"Photoelectron angular distributions for the two-photon ionization of atoms by ultraviolet laser pulses","authors":"Zichao Liu , Wanhong Wen , Yingbin Li , Benhai Yu , Cheng Huang","doi":"10.1016/j.optlastec.2026.114839","DOIUrl":"10.1016/j.optlastec.2026.114839","url":null,"abstract":"<div><div>We theoretically study the two-photon ionization of H for the laser frequency range (0.25, 0.5) a.u. by numerically solving the time-dependent Schrödinger equation. The results show that the photoelectron angular distributions (PADs) are strongly dependent on the laser frequency. In the vicinity of the resonant frequency, the photoelectron momentum distributions show a doublet structure. For the inner ring, the population in the parallel direction is larger than the perpendicular direction, and the distribution shows little variation with the laser frequency. For the outer ring, as the laser frequency increases, the electron emissions transfer from the parallel to perpendicular direction. Below the resonant frequency region, the proportion of the perpendicular emissions increases with the laser frequency decreasing. Above the resonant frequency region, the electron emissions transfer from the perpendicular to parallel direction, and finally the dominant emission direction becomes the parallel direction. By separating the contributions from the outgoing s wave, d wave and their interference, the strong dependency of the PADs on the laser frequency can be well understood. These results provide deep insights into the two-photon ionization by ultraviolet laser pulses.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114839"},"PeriodicalIF":5.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079660","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 : 2026-05-01Epub Date: 2026-01-19DOI: 10.1016/j.optlastec.2026.114735
Yishan Chen , Xuqiang Wu , Weixin Qiu , Deng Pan , Benli Yu , Zhiqiang Wang
Fiber Kerr resonators hold immense potential for coherent soliton comb generation and provide good platforms for exploring complex dynamics of nonlinear systems. However, Kerr cavity soliton (CS) states in fiber Kerr resonators are sensitive to perturbations, leading to instabilities, such as soliton breathing or annihilation. Leveraging Genetic Algorithm to overcome these instabilities and explore experimental conditions for stable CS generation and optimization presents significant hurdles, as multistable behavior of CS involves intricate interactions. In this study, we present a novel classification-prioritized optimization framework within multi-objective optimization algorithms, developing an enhanced Hierarchical Cost-Dominate Genetic Algorithm (HCD-GA) that enables accurate control of conditions for stable CS formation in fiber Kerr resonators. HCD-GA achieves global convergence by masterfully balancing competing objectives, demonstrating its potential in finding desired CS states and performing multi-objective optimization. The critical role of hyperparameters on the performances of HCD-GA is also discussed. This work presents the first application of multi-objective optimization algorithms to acquire target states in Kerr resonators, which is key to unlocking the full potential of CS.
{"title":"On-demand access to desired soliton comb states in fiber kerr resonators using a hierarchical cost-dominate genetic algorithm","authors":"Yishan Chen , Xuqiang Wu , Weixin Qiu , Deng Pan , Benli Yu , Zhiqiang Wang","doi":"10.1016/j.optlastec.2026.114735","DOIUrl":"10.1016/j.optlastec.2026.114735","url":null,"abstract":"<div><div>Fiber Kerr resonators hold immense potential for coherent soliton comb generation and provide good platforms for exploring complex dynamics of nonlinear systems. However, Kerr cavity soliton (CS) states in fiber Kerr resonators are sensitive to perturbations, leading to instabilities, such as soliton breathing or annihilation. Leveraging Genetic Algorithm to overcome these instabilities and explore experimental conditions for stable CS generation and optimization presents significant hurdles, as multistable behavior of CS involves intricate interactions. In this study, we present a novel classification-prioritized optimization framework within multi-objective optimization algorithms, developing an enhanced Hierarchical Cost-Dominate Genetic Algorithm (HCD-GA) that enables accurate control of conditions for stable CS formation in fiber Kerr resonators. HCD-GA achieves global convergence by masterfully balancing competing objectives, demonstrating its potential in finding desired CS states and performing multi-objective optimization. The critical role of hyperparameters on the performances of HCD-GA is also discussed. This work presents the first application of multi-objective optimization algorithms to acquire target states in Kerr resonators, which is key to unlocking the full potential of CS.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114735"},"PeriodicalIF":5.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036332","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 : 2026-05-01Epub Date: 2026-01-23DOI: 10.1016/j.optlastec.2026.114811
Qinhua Li , Rende Ma , Xiaoping Li , Mingsheng Niu , Hongzhong Cao , Yue Pan , Xuzhen Gao , Shitong Xu , Dengwang Li
The optical sensors working near the dispersion turning point (DTP) can achieve ultra-high sensitivity. However, their sensitivities will decay rapidly when the working points deviate from DTP. Here, we improve the sensitivity of a fiber Mach–Zehnder interferometer (MZI) by simultaneously utilizing two DTPs. The principle depends on the quasi-symmetric distribution of refractive index dispersion of single-mode-fiber. A Grin-lenses-coupled fiber MZI is proposed, which can greatly simplify the analysis of dual-DTP sensitization scheme. It is found that, when the working point deviates from DTP by the same distance, the sensitivity of dual-DTP enhanced sensor can be more than twice as high as that of single-DTP enhanced sensor. When the relative change rate of the sensitivity is 1%, the sensing bandwidth can be improved by dozens of times. This dual-DTP sensitization scheme also provides a reference for improving the sensitivity of other optical sensors.
{"title":"Dual dispersion turning point co-enhanced fiber sensor","authors":"Qinhua Li , Rende Ma , Xiaoping Li , Mingsheng Niu , Hongzhong Cao , Yue Pan , Xuzhen Gao , Shitong Xu , Dengwang Li","doi":"10.1016/j.optlastec.2026.114811","DOIUrl":"10.1016/j.optlastec.2026.114811","url":null,"abstract":"<div><div>The optical sensors working near the dispersion turning point (DTP) can achieve ultra-high sensitivity. However, their sensitivities will decay rapidly when the working points deviate from DTP. Here, we improve the sensitivity of a fiber Mach–Zehnder interferometer (MZI) by simultaneously utilizing two DTPs. The principle depends on the quasi-symmetric distribution of refractive index dispersion of single-mode-fiber. A Grin-lenses-coupled fiber MZI is proposed, which can greatly simplify the analysis of dual-DTP sensitization scheme. It is found that, when the working point deviates from DTP by the same distance, the sensitivity of dual-DTP enhanced sensor can be more than twice as high as that of single-DTP enhanced sensor. When the relative change rate of the sensitivity is 1%, the sensing bandwidth can be improved by dozens of times. This dual-DTP sensitization scheme also provides a reference for improving the sensitivity of other optical sensors.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114811"},"PeriodicalIF":5.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039670","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}
A novel underwater active polarization imaging system is proposed, which could output realtime de-backscatter videos at 25 fps. The limitation of most existing polarization imaging systems—their inability to provide real-time de-backscatter video output—has been addressed, overcoming a major obstacle that had hindered the application of polarization imaging technology in video capture scenarios. In this system, the orthogonal polarization switching position is relocated from the camera side to the light source side. A 4 × 8 array orthogonal polarization state LED light source is adopted, and two groups of lamp beads with differential polarization states are arranged alternately to reduce the influence of light field switching. A high-sensitivity image sensor (pixel size: 12.0 μm × 12.0 μm; sensitivity: 120,000 mV/lux·@HCG) is integrated into the camera to adapt to high attenuation underwater environments.Precise hardware synchronization is achieved through a frame synchronization signal (50 Hz) generated by the camera, which controls the polarization state switching of the light source. FPGA-based image data encoding is employed to enable 12-bit grayscale image transmission via SDI. The image acquisition device transfers data to the host computer, where real-time de-backscatter video output is accomplished through differential polarization image processing in the host software. The gradient turbidity experiment results demonstrated that the proposed system exhibited excellent backscatter suppression performance.(Compared with ordinary LED light sources, the EME value of the output image in this system is increased by 20.12 on average within the turbidity range of 0–17.35). Dynamic target imaging experiments confirmed its effectiveness in moving-scene applications. Additionally, a comparative study was conducted using light sources of different wavelengths (red vs. yellow), verifying that the yellow spectrum (550 nm) provided better underwater imaging performance. The proposed system resolves the mechanical latency issues inherent in conventional differential polarization methods while maintaining superior de-backscattering performance in high attenuation underwater environments. Through hardware synchronization and data optimization, high-quality real-time image processing and output are achieved. The system demonstrates compatibility with various cameras featuring frame synchronization signal output, providing a robust technical solution for real-time underwater de-backscatter imaging applications in industrial inspection and marine exploration.
{"title":"Underwater polarimetric imaging system for real-time de-backscatter video application","authors":"Houde Wu, Ruiqi Guo, Jiachang Wan, Hongchang Wang, Xiaoxue Gu, Changjiang Liu","doi":"10.1016/j.optlastec.2026.114654","DOIUrl":"10.1016/j.optlastec.2026.114654","url":null,"abstract":"<div><div>A novel underwater active polarization imaging system is proposed, which could output realtime de-backscatter videos at 25 fps. The limitation of most existing polarization imaging systems—their inability to provide real-time de-backscatter video output—has been addressed, overcoming a major obstacle that had hindered the application of polarization imaging technology in video capture scenarios. In this system, the orthogonal polarization switching position is relocated from the camera side to the light source side. A 4 × 8 array orthogonal polarization state LED light source is adopted, and two groups of lamp beads with differential polarization states are arranged alternately to reduce the influence of light field switching. A high-sensitivity image sensor (pixel size: 12.0 μm × 12.0 μm; sensitivity: 120,000 mV/lux·@HCG) is integrated into the camera to adapt to high attenuation underwater environments.Precise hardware synchronization is achieved through a frame synchronization signal (50 Hz) generated by the camera, which controls the polarization state switching of the light source. FPGA-based image data encoding is employed to enable 12-bit grayscale image transmission via SDI. The image acquisition device transfers data to the host computer, where real-time de-backscatter video output is accomplished through differential polarization image processing in the host software. The gradient turbidity experiment results demonstrated that the proposed system exhibited excellent backscatter suppression performance.(Compared with ordinary LED light sources, the EME value of the output image in this system is increased by 20.12 on average within the turbidity range of 0–17.35). Dynamic target imaging experiments confirmed its effectiveness in moving-scene applications. Additionally, a comparative study was conducted using light sources of different wavelengths (red vs. yellow), verifying that the yellow spectrum (550 nm) provided better underwater imaging performance. The proposed system resolves the mechanical latency issues inherent in conventional differential polarization methods while maintaining superior de-backscattering performance in high attenuation underwater environments. Through hardware synchronization and data optimization, high-quality real-time image processing and output are achieved. The system demonstrates compatibility with various cameras featuring frame synchronization signal output, providing a robust technical solution for real-time underwater de-backscatter imaging applications in industrial inspection and marine exploration.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114654"},"PeriodicalIF":5.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039822","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 : 2026-05-01Epub Date: 2026-01-20DOI: 10.1016/j.optlastec.2026.114738
Ziao Yan , Nan Su , Zhanpeng Sun , Jiapeng Zhang , Mingyang Zheng , Yaxuan Gao , Guang Yang
The gradient-structured powder beds by hierarchically combining coarse and fine powder were designed for the thick-layer LPBF in this study. The dynamic melting processes of the different powder beds including the pure fine powder bed, the pure coarse powder bed, the gradient C/F and F/C typed beds were observed using the high-speed micro-focus X-ray imaging system. Then the morphology and microstructure of the melt tracks were characterized by the optical microscopy, the white light interferometry and EBSD. Furthermore, the influence mechanism of the particle size on heat transfer for the gradient-structured powder beds was revealed. The results show that the C/F beds can achieve a balanced improvement in improving the melting wettability, stability of the molten pool and reducing spatters. The melt track surface of the C/F = 100/300 bed (coarse powder with 100 μm layer at upper and fine powder with 300 μm layer at lower) is relatively smooth with few surface defects. Compared to the pure coarse and fine powder bed, its grains become finer and relatively uniform, with the maximum size reduced by more than 41 % and 19 %, respectively. But further increasing the coarse particle layer causes a rapid increase in the number of spatters, and the melt track quality deteriorates instead. The melt pool of the F/C typed beds fluctuates violently and many unfused coarse particles at lower layer float up, resulting in rough surfaces. The monotonic increase of the contact area between the melt pool and the surrounding particles for the C/F beds dominates faster heat transfer rate, contributing to the improvements of the melt-pool flow and the forming quality. This work provides a new approach and deep understanding for enhancing the forming quality of the thick-layer LPBF.
{"title":"Dynamic process and mechanism of the laser-based particle-size driven gradient-structured beds fusion","authors":"Ziao Yan , Nan Su , Zhanpeng Sun , Jiapeng Zhang , Mingyang Zheng , Yaxuan Gao , Guang Yang","doi":"10.1016/j.optlastec.2026.114738","DOIUrl":"10.1016/j.optlastec.2026.114738","url":null,"abstract":"<div><div>The gradient-structured powder beds by hierarchically combining coarse and fine powder were designed for the thick-layer LPBF in this study. The dynamic melting processes of the different powder beds including the pure fine powder bed, the pure coarse powder bed, the gradient C/F and F/C typed beds were observed using the high-speed micro-focus X-ray imaging system. Then the morphology and microstructure of the melt tracks were characterized by the optical microscopy, the white light interferometry and EBSD. Furthermore, the influence mechanism of the particle size on heat transfer for the gradient-structured powder beds was revealed. The results show that the C/F beds can achieve a balanced improvement in improving the melting wettability, stability of the molten pool and reducing spatters. The melt track surface of the C/F = 100/300 bed (coarse powder with 100 μm layer at upper and fine powder with 300 μm layer at lower) is relatively smooth with few surface defects. Compared to the pure coarse and fine powder bed, its grains become finer and relatively uniform, with the maximum size reduced by more than 41 % and 19 %, respectively. But further increasing the coarse particle layer causes a rapid increase in the number of spatters, and the melt track quality deteriorates instead. The melt pool of the F/C typed beds fluctuates violently and many unfused coarse particles at lower layer float up, resulting in rough surfaces. The monotonic increase of the contact area between the melt pool and the surrounding particles for the C/F beds dominates faster heat transfer rate, contributing to the improvements of the melt-pool flow and the forming quality. This work provides a new approach and deep understanding for enhancing the forming quality of the thick-layer LPBF.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114738"},"PeriodicalIF":5.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039825","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 : 2026-05-01Epub Date: 2026-01-21DOI: 10.1016/j.optlastec.2026.114752
Puyousen Zhang, Yiwen Li, Yao Li, Binbin Pei, Yinghong Li
Infrared image simulation is a key component of infrared technology. This paper proposes an Irradiance Mapping (IM) method for infrared image simulation, integrating Progressive Irradiance Calculation (PIC) with ray casting (RC) to eliminate the random noise inherent in conventional ray-tracing techniques. The method adopts hierarchical data reuse across the radiative transfer matrix, PIC computations, and irradiance maps. Validations show that IM performs excellently in secondary diffuse reflection zones, achieves noise-free results, and significantly accelerates multi-angle simulations. Compared with Monte Carlo Ray Tracing (MCRT) methods, IM enhances computational efficiency while maintaining high-precision radiometric output, establishing a new paradigm for deterministic infrared simulation.
{"title":"Irradiance mapping-driven infrared image simulation: Achieving noise-free accuracy with high data reusability","authors":"Puyousen Zhang, Yiwen Li, Yao Li, Binbin Pei, Yinghong Li","doi":"10.1016/j.optlastec.2026.114752","DOIUrl":"10.1016/j.optlastec.2026.114752","url":null,"abstract":"<div><div>Infrared image simulation is a key component of infrared technology. This paper proposes an Irradiance Mapping (IM) method for infrared image simulation, integrating Progressive Irradiance Calculation (PIC) with ray casting (RC) to eliminate the random noise inherent in conventional ray-tracing techniques. The method adopts hierarchical data reuse across the radiative transfer matrix, PIC computations, and irradiance maps. Validations show that IM performs excellently in secondary diffuse reflection zones, achieves noise-free results, and significantly accelerates multi-angle simulations. Compared with Monte Carlo Ray Tracing (MCRT) methods, IM enhances computational efficiency while maintaining high-precision radiometric output, establishing a new paradigm for deterministic infrared simulation.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114752"},"PeriodicalIF":5.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039293","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 : 2026-05-01Epub Date: 2026-01-21DOI: 10.1016/j.optlastec.2026.114667
Erick Ipus , Luis Ordóñez , Alexander León Ramírez , Omel Mendoza-Yero
In this manuscript a diffraction-based method for generating focused vortex beams with dynamic control over their axial complex field is introduced and experimentally demonstrated. The vortex beams are optically designed through the combination of a freeform diffractive lens and a spiral phase plate. This particular integration of optical elements enables demonstrated on-axis beam shaping capabilities within the depth of focus to be extended to vortex beams. Using the proposed beam generation method, focused vortex beams with user-defined axial optical parameters, e.g., axial amplitude and phase profiles can be generated via coherent light diffraction by a single-phase element. The beam shaping functionality achieved by this method is expected to enhance the applicability of vortex beams in diverse research areas, including optical tweezers, super-resolution microscopy, and quantum cryptography.
{"title":"Tunable focused vortex beams","authors":"Erick Ipus , Luis Ordóñez , Alexander León Ramírez , Omel Mendoza-Yero","doi":"10.1016/j.optlastec.2026.114667","DOIUrl":"10.1016/j.optlastec.2026.114667","url":null,"abstract":"<div><div>In this manuscript a diffraction-based method for generating focused vortex beams with dynamic control over their axial complex field is introduced and experimentally demonstrated. The vortex beams are optically designed through the combination of a freeform diffractive lens and a spiral phase plate. This particular integration of optical elements enables demonstrated on-axis beam shaping capabilities within the depth of focus to be extended to vortex beams. Using the proposed beam generation method, focused vortex beams with user-defined axial optical parameters, e.g., axial amplitude and phase profiles can be generated via coherent light diffraction by a single-phase element. The beam shaping functionality achieved by this method is expected to enhance the applicability of vortex beams in diverse research areas, including optical tweezers, super-resolution microscopy, and quantum cryptography.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114667"},"PeriodicalIF":5.0,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039228","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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