Pub Date : 2026-01-17DOI: 10.1016/j.optlastec.2026.114760
Yuansheng Ma, Ziyang Zhang, Meiqi Liu, Pan Wang, Zhi Wang, Yange Liu, Bo Liu
We propose a patch-based transformer neural network to capture intrinsic temporal-spectral correlations in time-stretched spectral evolutions of adjacent, temporally supra-localized soliton molecular units, thereby enabling high-fidelity prediction of their complex dynamics. Experimentally, we constructed a passively mode-locked fiber laser operating in the anomalous-dispersion regime, incorporating real-time spectral monitoring via time-stretched dispersive Fourier transform (TS-DFT). This setup allowed direct observation of the intricate real-time evolution of temporally supra-localized soliton molecular distributions. Remarkably, the patch-transformer model accurately predicts the spectral interference patterns, temporal separations, and sliding phase evolutions between the soliton molecule and the interacting single soliton within the compound soliton molecular units by learning sequential temporal-spectral features solely from the TS-DFT spectra of their neighboring supra-localized counterparts. This achievement bridges a critical gap in the long-term predictability of complex temporally supra-localized distributed soliton molecular dynamics. By effectively extracting temporal-spectral correlation features embedded in TS-DFT spectra, the patch-transformer framework provides a powerful, data-driven tool for forecasting correlated soliton molecular compound behavior across extended temporal scales and multidimensional parameter spaces.
{"title":"Patch-transformer prediction of supra-localized soliton-molecule dynamics from time-stretched spectra","authors":"Yuansheng Ma, Ziyang Zhang, Meiqi Liu, Pan Wang, Zhi Wang, Yange Liu, Bo Liu","doi":"10.1016/j.optlastec.2026.114760","DOIUrl":"10.1016/j.optlastec.2026.114760","url":null,"abstract":"<div><div>We propose a patch-based transformer neural network to capture intrinsic temporal-spectral correlations in time-stretched spectral evolutions of adjacent, temporally supra-localized soliton molecular units, thereby enabling high-fidelity prediction of their complex dynamics. Experimentally, we constructed a passively mode-locked fiber laser operating in the anomalous-dispersion regime, incorporating real-time spectral monitoring via time-stretched dispersive Fourier transform (TS-DFT). This setup allowed direct observation of the intricate real-time evolution of temporally supra-localized soliton molecular distributions. Remarkably, the patch-transformer model accurately predicts the spectral interference patterns, temporal separations, and sliding phase evolutions between the soliton molecule and the interacting single soliton within the compound soliton molecular units by learning sequential temporal-spectral features solely from the TS-DFT spectra of their neighboring supra-localized counterparts. This achievement bridges a critical gap in the long-term predictability of complex temporally supra-localized distributed soliton molecular dynamics. By effectively extracting temporal-spectral correlation features embedded in TS-DFT spectra, the patch-transformer framework provides a powerful, data-driven tool for forecasting correlated soliton molecular compound behavior across extended temporal scales and multidimensional parameter spaces.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114760"},"PeriodicalIF":5.0,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981948","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 : 2026-01-17DOI: 10.1016/j.optlastec.2026.114763
Lingkai Huang , Yirui Zhu , Liyang Wang , Ningning Luo , Mingwei Lu , Tomas E. Gomez Alvarez-Arenas , Xingdao He , Jiulin Shi
Viscoelastic properties of pathological changes in brain tissue are key biomarkers for clinical neurological diseases. Clinically, shear wave elastography is an ultrasound technique capable of quantitatively assessing tissue elasticity, however, its application is limited by submillimeter spatial resolution. In this work, we developed an air-coupled ultrasound transducer-based optical coherence elastography system (AcUT-OCE), which enables non-contact quantitative elastography of brain tissue with micrometer-scale resolution. A Kelvin-Voigt fractional derivative model (KVFD) incorporating a power-law- constraint (PC-KVFD) was established to quantitatively evaluate the viscoelasticity of brain tissue. The results of the phantom experiment demonstrate that the phase velocity corrected using the PC-KVFD model exhibits a power-law relationship, with its magnitude being higher than the uncorrected measured values. The storage modulus and loss modulus of the phantom were calculated to be within the ranges of 6.1–10.3 kPa and 1.8–4.6 kPa, respectively. Then, an in ex vivo porcine brain experiment was conducted, in which the storage modulus and loss modulus of the brain tissue were estimated to be in the ranges of 4.5–8 kPa and 2–4 kPa, respectively. Subsequently, we compared the accuracies of the linear model, KVFD model, and PC-KVFD model in calculating viscoelasticity. The PC-KVFD model exhibits superior performance in terms of viscoelastic frequency dependence curves, with R2 (coefficient of determination) values exceeding 0.99 for the storage modulus and 0.98 for the loss modulus, indicating an excellent goodness of fit. Overall, the AcUT-OCE technique combined with the PC-KVFD model, enables non-contact, high-resolution, and quantitative assessment of brain tissue viscoelasticity.
{"title":"Characterizing brain tissue viscoelasticity using air-coupled ultrasound transducer-based optical coherence elastography with power-law-constrained Kelvin-Voigt fractional derivative model☆★","authors":"Lingkai Huang , Yirui Zhu , Liyang Wang , Ningning Luo , Mingwei Lu , Tomas E. Gomez Alvarez-Arenas , Xingdao He , Jiulin Shi","doi":"10.1016/j.optlastec.2026.114763","DOIUrl":"10.1016/j.optlastec.2026.114763","url":null,"abstract":"<div><div>Viscoelastic properties of pathological changes in brain tissue are key biomarkers for clinical neurological diseases. Clinically, shear wave elastography is an ultrasound technique capable of quantitatively assessing tissue elasticity, however, its application is limited by submillimeter spatial resolution. In this work, we developed an air-coupled ultrasound transducer-based optical coherence elastography system (AcUT-OCE), which enables non-contact quantitative elastography of brain tissue with micrometer-scale resolution. A Kelvin-Voigt fractional derivative model (KVFD) incorporating a power-law- constraint (PC-KVFD) was established to quantitatively evaluate the viscoelasticity of brain tissue. The results of the phantom experiment demonstrate that the phase velocity corrected using the PC-KVFD model exhibits a power-law relationship, with its magnitude being higher than the uncorrected measured values. The storage modulus and loss modulus of the phantom were calculated to be within the ranges of 6.1–10.3 kPa and 1.8–4.6 kPa, respectively. Then, an in <em>ex vivo</em> porcine brain experiment was conducted, in which the storage modulus and loss modulus of the brain tissue were estimated to be in the ranges of 4.5–8 kPa and 2–4 kPa, respectively. Subsequently, we compared the accuracies of the linear model, KVFD model, and PC-KVFD model in calculating viscoelasticity. The PC-KVFD model exhibits superior performance in terms of viscoelastic frequency dependence curves, with R<sup>2</sup> (coefficient of determination) values exceeding 0.99 for the storage modulus and 0.98 for the loss modulus, indicating an excellent goodness of fit. Overall, the AcUT-OCE technique combined with the PC-KVFD model, enables non-contact, high-resolution, and quantitative assessment of brain tissue viscoelasticity.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114763"},"PeriodicalIF":5.0,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981949","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 : 2026-01-16DOI: 10.1016/j.optlastec.2026.114707
Liang Mei , Hangyi Liu , Xuekai Hong , Xinhong Wang , Yuan Cheng , Xinglong Yang , Zheng Wang , Wei Peng , Zheng Kong
Scheimpflug lidar (SLidar) has emerged as a pivotal tool in atmospheric remote sensing, providing high-resolution detection of aerosol spatiotemporal distributions and their optical-microphysical properties. By exploiting geometrical optics principles, range-resolved atmospheric lidar signals can be obtained from pixel intensities. However, the incident angles of scattered light, varying with the detection distance, could introduce quantum efficiency (QE) variations in tilted image sensors that distort lidar signals, particularly in near-field regimes. In this work, we propose a universal, physics-based angular response correction model (ARCM) that unifies laser scattering angle, image sensor tilt, and receiver off-axis light effects into a pixel-level correction framework. The ARCM introduces a pixelwise correction factor to compensate for QE-induced signal distortions. The performance of the ARCM was systematically validated through theoretical simulations and atmospheric experiments using three SLidar systems with distinct optical configurations, covering both near-horizontal and vertical detection scenarios. Our results reveal discrepancies in the QE angular response among the three SLidar configurations, with extinction coefficient retrieval errors between uncorrected and corrected signals ranging from 3% to 10% at the minimum detection range. Besides, six-day horizontal scanning experiments were also conducted, and the ARCM-corrected extinction coefficients showed strong agreement with in-situ PM2.5 measurements, with a correlation coefficient of 0.904. Furthermore, quantitative analysis shows that focal length serves as the dominant factor suppressing QE fluctuations, while sensor tilt determines the operational region on the QE curve, resulting in a non-monotonic coupling between SLidar configurations and relative QEs. This work significantly advances the measurement accuracy of the SLidar signal particularly in close range, thereby enhancing its reliability for critical applications in aerosol sensing.
{"title":"Influence and calibration of the angular response of the image sensor on lidar profiles in Scheimpflug lidar techniques","authors":"Liang Mei , Hangyi Liu , Xuekai Hong , Xinhong Wang , Yuan Cheng , Xinglong Yang , Zheng Wang , Wei Peng , Zheng Kong","doi":"10.1016/j.optlastec.2026.114707","DOIUrl":"10.1016/j.optlastec.2026.114707","url":null,"abstract":"<div><div>Scheimpflug lidar (SLidar) has emerged as a pivotal tool in atmospheric remote sensing, providing high-resolution detection of aerosol spatiotemporal distributions and their optical-microphysical properties. By exploiting geometrical optics principles, range-resolved atmospheric lidar signals can be obtained from pixel intensities. However, the incident angles of scattered light, varying with the detection distance, could introduce quantum efficiency (QE) variations in tilted image sensors that distort lidar signals, particularly in near-field regimes. In this work, we propose a universal, physics-based angular response correction model (ARCM) that unifies laser scattering angle, image sensor tilt, and receiver off-axis light effects into a pixel-level correction framework. The ARCM introduces a pixelwise correction factor to compensate for QE-induced signal distortions. The performance of the ARCM was systematically validated through theoretical simulations and atmospheric experiments using three SLidar systems with distinct optical configurations, covering both near-horizontal and vertical detection scenarios. Our results reveal discrepancies in the QE angular response among the three SLidar configurations, with extinction coefficient retrieval errors between uncorrected and corrected signals ranging from 3% to 10% at the minimum detection range. Besides, six-day horizontal scanning experiments were also conducted, and the ARCM-corrected extinction coefficients showed strong agreement with in-situ PM<sub>2.5</sub> measurements, with a correlation coefficient of 0.904. Furthermore, quantitative analysis shows that focal length serves as the dominant factor suppressing QE fluctuations, while sensor tilt determines the operational region on the QE curve, resulting in a non-monotonic coupling between SLidar configurations and relative QEs. This work significantly advances the measurement accuracy of the SLidar signal particularly in close range, thereby enhancing its reliability for critical applications in aerosol sensing.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114707"},"PeriodicalIF":5.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981986","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 : 2026-01-16DOI: 10.1016/j.optlastec.2026.114743
Dong Yan , Mingyang Li , Yunfei Ma , Xiaoming Duan , Jinhe Yuan , Yunpeng Wang , Youlun Ju , Wenlong Yang
A high-energy, single-frequency, injection-seeded Ho:YAG master oscillator power amplifier (MOPA) system was proposed, which incorporates a novel ring resonator constructed with three corner-cube retroreflectors (CCRs). This compact three-CCR design effectively mitigates the substantial transverse footprint inherent to conventional dual-CCR long cavities, while preserving their exceptional misalignment tolerance. The slave oscillator, seeded by a single-longitudinal-mode (SLM) Ho:YAG non-planar ring oscillator (NPRO) at 2090.69 nm and Q-switched at 100 Hz, generated 6.8mJ pulses with a duration of 143 ns. Subsequent amplification in a single-pass Ho:YAG amplifier achieved a maximum output energy of 20.4mJ, corresponding to a gain of 4.8 dB. The system exhibits excellent energy stability over 40 min, with a mean pulse energy of 19.55 mJ and a standard deviation (SD) of 0.372 mJ, corresponding to a relative SD of 1.9 %. The output beam exhibited near-diffraction-limited quality, with beam quality factors of Mx2 = 1.02 and My2 = 1.17. Heterodyne measurements confirmed a spectral linewidth of 4.87 MHz. Quantitative robustness evaluation revealed that a 50 % power reduction was induced by translational displacements of 0.31 mm or angular tilts exceeding 1.8° for the most sensitive CCR. This work establishes a robust and compact laser architecture suitable for demanding applications requiring high-energy, single-frequency pulses in the 2 μm spectral region.
{"title":"Compact, Misalignment-Tolerant Ho:YAG MOPA system based on a novel Three-Corner-Cube-Retroreflector ring cavity","authors":"Dong Yan , Mingyang Li , Yunfei Ma , Xiaoming Duan , Jinhe Yuan , Yunpeng Wang , Youlun Ju , Wenlong Yang","doi":"10.1016/j.optlastec.2026.114743","DOIUrl":"10.1016/j.optlastec.2026.114743","url":null,"abstract":"<div><div>A high-energy, single-frequency, injection-seeded Ho:YAG master oscillator power amplifier (MOPA) system was proposed, which incorporates a novel ring resonator constructed with three corner-cube retroreflectors (CCRs). This compact three-CCR design effectively mitigates the substantial transverse footprint inherent to conventional dual-CCR long cavities, while preserving their exceptional misalignment tolerance. The slave oscillator, seeded by a single-longitudinal-mode (SLM) Ho:YAG non-planar ring oscillator (NPRO) at 2090.69 nm and Q-switched at 100 Hz, generated 6.8mJ pulses with a duration of 143 ns. Subsequent amplification in a single-pass Ho:YAG amplifier achieved a maximum output energy of 20.4mJ, corresponding to a gain of 4.8 dB. The system exhibits excellent energy stability over 40 min, with a mean pulse energy of 19.55 mJ and a standard deviation (SD) of 0.372 mJ, corresponding to a relative SD of 1.9 %. The output beam exhibited near-diffraction-limited quality, with beam quality factors of <em>M<sub>x</sub></em><sup>2</sup> = 1.02 and <em>M<sub>y</sub></em><sup>2</sup> = 1.17. Heterodyne measurements confirmed a spectral linewidth of 4.87 MHz. Quantitative robustness evaluation revealed that a 50 % power reduction was induced by translational displacements of 0.31 mm or angular tilts exceeding 1.8° for the most sensitive CCR. This work establishes a robust and compact laser architecture suitable for demanding applications requiring high-energy, single-frequency pulses in the 2 μm spectral region.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114743"},"PeriodicalIF":5.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981947","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 : 2026-01-16DOI: 10.1016/j.optlastec.2026.114721
Changqing Liu , Xiongshuai Ji , Pengju Huo , Xiangyang Chen , Hanfang Xie , Weimin Long , Yajie Guo , Haiyan Chen
Laser beam oscillation has demonstrated notable effectiveness in welding by modulating mass and heat transfer within narrow and deep molten pools. However, in laser cladding, which is characterized by a shallower and wider molten pool, the influence of oscillation patterns remains insufficiently understood. In this study, a three-dimensional finite element model coupling temperature and fluid fields was developed to investigate the effects of five oscillation modes (non-oscillation, circular, infinity-shaped, longitudinal, and transverse) on the thermal-fluid behavior and microstructural evolution of single-track Ni60 coatings. Simulation and experimental results indicate that oscillation-induced stirring expands the molten pool length and promotes a more uniform energy distribution, thereby mitigating local overheating. This effect helps establish a more stable melt flow, improves the geometric consistency of the cladding, and effectively suppresses spatter and hump-shaped formation defects. In addition, oscillation reduces the axial temperature gradient (G), while increasing the solidification rate (R), which favors the formation of equiaxed grains. Among all tested modes, circular oscillation produced the most stable melt flow and the most uniform thermal field. Compared with the non-oscillating mode, circular oscillation lowered the molten-pool peak temperature by approximately 1000 K, reduced the mean grain size by about 60 %, increased microhardness by roughly 45 %, and decreased the average friction coefficient by about 17 %. It should be noted that microstructural evolution in the cladding layer is primarily governed by the thermal history, whereas oscillation-induced shear forces have a pronounced effect on layer formation and defect suppression. These findings highlight laser beam oscillation, particularly the circular mode, as a promising strategy for tailoring melt dynamics, controlling solidification pathways, and enhancing the structure–property relationships in high-performance laser-cladded coatings.
{"title":"Oscillation-induced improvements in the microstructure and properties of laser cladding: A comparison among different patterns","authors":"Changqing Liu , Xiongshuai Ji , Pengju Huo , Xiangyang Chen , Hanfang Xie , Weimin Long , Yajie Guo , Haiyan Chen","doi":"10.1016/j.optlastec.2026.114721","DOIUrl":"10.1016/j.optlastec.2026.114721","url":null,"abstract":"<div><div>Laser beam oscillation has demonstrated notable effectiveness in welding by modulating mass and heat transfer within narrow and deep molten pools. However, in laser cladding, which is characterized by a shallower and wider molten pool, the influence of oscillation patterns remains insufficiently understood. In this study, a three-dimensional finite element model coupling temperature and fluid fields was developed to investigate the effects of five oscillation modes (non-oscillation, circular, infinity-shaped, longitudinal, and transverse) on the thermal-fluid behavior and microstructural evolution of single-track Ni60 coatings. Simulation and experimental results indicate that oscillation-induced stirring expands the molten pool length and promotes a more uniform energy distribution, thereby mitigating local overheating. This effect helps establish a more stable melt flow, improves the geometric consistency of the cladding, and effectively suppresses spatter and hump-shaped formation defects. In addition, oscillation reduces the axial temperature gradient (G), while increasing the solidification rate (R), which favors the formation of equiaxed grains. Among all tested modes, circular oscillation produced the most stable melt flow and the most uniform thermal field. Compared with the non-oscillating mode, circular oscillation lowered the molten-pool peak temperature by approximately 1000 K, reduced the mean grain size by about 60 %, increased microhardness by roughly 45 %, and decreased the average friction coefficient by about 17 %. It should be noted that microstructural evolution in the cladding layer is primarily governed by the thermal history, whereas oscillation-induced shear forces have a pronounced effect on layer formation and defect suppression. These findings highlight laser beam oscillation, particularly the circular mode, as a promising strategy for tailoring melt dynamics, controlling solidification pathways, and enhancing the structure–property relationships in high-performance laser-cladded coatings.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114721"},"PeriodicalIF":5.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981945","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 : 2026-01-16DOI: 10.1016/j.optlastec.2026.114749
Kai Song , Hongrui Liu , Yaoxing Bian , Dong Wang , Lei Han , Runrui Li , Shijun Zhao , Futong Zhang , Hongda Ge , Shuangping Han , Liantuan Xiao
Single-photon imaging is an exceptionally sensitive imaging technique, serving a crucial role in various scientific research and industrial applications. However, the noise arising from random detection and inherent limitations of detector greatly compromise imaging quality. Here, we demonstrate a robust single-photon single-pixel imaging technique. By employing a dual-stage strategy, the technique seamlessly integrates denoising with image reconstruction, effectively mitigating noise interference in extremely low-light scenes. And the ability to autonomously construct supervision from available information allows this technique to operate across diverse scenarios without training on any dataset. A series of laboratory and outdoor far-field experiments demonstrate its capability of high-quality imaging. Despite illumination conditions as low as 1 photon per pixel and a 12 dB fluctuation in the detection signal-to-noise ratio, the proposed technique consistently maintains stable imaging quality.
{"title":"Robust single-photon single-pixel imaging with self-supervised deep learning","authors":"Kai Song , Hongrui Liu , Yaoxing Bian , Dong Wang , Lei Han , Runrui Li , Shijun Zhao , Futong Zhang , Hongda Ge , Shuangping Han , Liantuan Xiao","doi":"10.1016/j.optlastec.2026.114749","DOIUrl":"10.1016/j.optlastec.2026.114749","url":null,"abstract":"<div><div>Single-photon imaging is an exceptionally sensitive imaging technique, serving a crucial role in various scientific research and industrial applications. However, the noise arising from random detection and inherent limitations of detector greatly compromise imaging quality. Here, we demonstrate a robust single-photon single-pixel imaging technique. By employing a dual-stage strategy, the technique seamlessly integrates denoising with image reconstruction, effectively mitigating noise interference in extremely low-light scenes. And the ability to autonomously construct supervision from available information allows this technique to operate across diverse scenarios without training on any dataset. A series of laboratory and outdoor far-field experiments demonstrate its capability of high-quality imaging. Despite illumination conditions as low as 1 photon per pixel and a 12 dB fluctuation in the detection signal-to-noise ratio, the proposed technique consistently maintains stable imaging quality.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"197 ","pages":"Article 114749"},"PeriodicalIF":5.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981946","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 : 2026-01-15DOI: 10.1016/j.optlastec.2026.114658
Ravil R. Agishev
Current trends in the development of remote sensing technologies indicate the emergence of a new class of CW range-resolved S-lidars (S comes from Scheimpflug) capable of effective environmental monitoring. Wide operating range and high range resolution are achieved by using a monostatic biaxial optical scheme with CW laser emitters and implementing the principles of triangular range control with position-sensitive detection. Along with, they gain a significantly increased depth-of-field through an unconventional S-configuration of the transceiver geometry. In this paper, we focus on ways of increasing the information content of S-lidar-based monitoring results. In general terms, we show capabilities of acquiring images representing the spatial distribution of optical properties of media under investigation along the sensing path. This means path-imaging excitement by an expanded probing beam and subsequent 2D array detection of echoes received from the depth-of-field formed by intersection of the beam and receiving field-of-view. We have given a dimensionless-parametric description of path-imaging S-lidar tactical performance in the range domain. Formation features and patterns of variability are analytically described with respect to the spatial position and dimensions of the configured path-imaging area. Details of extending the potential capabilities of CW S-lidars over traditional methods of utilizing them are discussed. Generalizations made and case studies considered clearly confirm the practicality and efficiency of developed approaches. Results of evaluation show the S-sensor capabilities to acquire and process images illustrating the spatial distribution of optical properties, regardless of the propagation medium, whether atmospheric- and aquatic-related environments or any others. And such a path-imaging can be implemented for different range scales from the lab-bench to the multi-kilometer path. All this indicates the broad prospects for the Path-Imaging S-lidar (PIS-lidar) class of laser remote sensors.
{"title":"Path-imaging CW S-lidars and achievable spatial selectivity in multiscale remote sensing","authors":"Ravil R. Agishev","doi":"10.1016/j.optlastec.2026.114658","DOIUrl":"10.1016/j.optlastec.2026.114658","url":null,"abstract":"<div><div>Current trends in the development of remote sensing technologies indicate the emergence of a new class of CW range-resolved S-lidars (S comes from Scheimpflug) capable of effective environmental monitoring. Wide operating range and high range resolution are achieved by using a monostatic biaxial optical scheme with CW laser emitters and implementing the principles of triangular range control with position-sensitive detection. Along with, they gain a significantly increased depth-of-field through an unconventional S-configuration of the transceiver geometry. In this paper, we focus on ways of increasing the information content of S-lidar-based monitoring results. In general terms, we show capabilities of acquiring images representing the spatial distribution of optical properties of media under investigation along the sensing path. This means path-imaging excitement by an expanded probing beam and subsequent 2D array detection of echoes received from the depth-of-field formed by intersection of the beam and receiving field-of-view. We have given a dimensionless-parametric description of path-imaging S-lidar tactical performance in the range domain. Formation features and patterns of variability are analytically described with respect to the spatial position and dimensions of the configured path-imaging area. Details of extending the potential capabilities of CW S-lidars over traditional methods of utilizing them are discussed. Generalizations made and case studies considered clearly confirm the practicality and efficiency of developed approaches. Results of evaluation show the S-sensor capabilities to acquire and process images illustrating the spatial distribution of optical properties, regardless of the propagation medium, whether atmospheric- and aquatic-related environments or any others. And such a path-imaging can be implemented for different range scales from the lab-bench to the multi-kilometer path. All this indicates the broad prospects for the Path-Imaging S-lidar (PIS-lidar) class of laser remote sensors.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"196 ","pages":"Article 114658"},"PeriodicalIF":5.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978624","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 : 2026-01-15DOI: 10.1016/j.optlastec.2026.114746
Yue Sun , Peng Yan , Qihang Sun , Shiqi Sun , Lixia Zhu , Chao Zhang , Xueshen Liu
Low-energy photoelectron holography (LEPH) is a powerful technique for ultrafast matter imaging, as it encodes time-resolved information about both the electron and parent ion dynamics. However, its clear observation is often hindered by dominant interference structures in photoelectron momentum distributions. Here, an isolated LEPH is revealed by introducing a 3.3 fs unipolar pulse in a few-cycle laser field. The numerical results obtained from solving the two-dimensional time-dependent Schrdinger equation align with those derived from the semiclassical two-step model. We demonstrate that the isolated LEPH arises from the interference between a single forward-rescattering electron and a direct electron. By tracing back to the initial state and the typical trajectories of the electrons, we find that the unipolar pulse not only reduces the number of collisions between electrons and parent ions, but also decreases the probability of the single forward rescattering electrons being captured by the parent ion into the Rydberg state, achieving the reconstruction of the LEPH. Moreover, our results show that introducing the unipolar pulses can provide a broader time window for probing the ultrafast dynamics of the electrons.
{"title":"Isolated low-energy photoelectron holography in a few-cycle laser field combined with a unipolar pulse","authors":"Yue Sun , Peng Yan , Qihang Sun , Shiqi Sun , Lixia Zhu , Chao Zhang , Xueshen Liu","doi":"10.1016/j.optlastec.2026.114746","DOIUrl":"10.1016/j.optlastec.2026.114746","url":null,"abstract":"<div><div>Low-energy photoelectron holography (LEPH) is a powerful technique for ultrafast matter imaging, as it encodes time-resolved information about both the electron and parent ion dynamics. However, its clear observation is often hindered by dominant interference structures in photoelectron momentum distributions. Here, an isolated LEPH is revealed by introducing a 3.3 fs unipolar pulse in a few-cycle laser field. The numerical results obtained from solving the two-dimensional time-dependent Schr<span><math><mrow><mover><mtext>o</mtext><mo>¨</mo></mover></mrow></math></span>dinger equation align with those derived from the semiclassical two-step model. We demonstrate that the isolated LEPH arises from the interference between a single forward-rescattering electron and a direct electron. By tracing back to the initial state and the typical trajectories of the electrons, we find that the unipolar pulse not only reduces the number of collisions between electrons and parent ions, but also decreases the probability of the single forward rescattering electrons being captured by the parent ion into the Rydberg state, achieving the reconstruction of the LEPH. Moreover, our results show that introducing the unipolar pulses can provide a broader time window for probing the ultrafast dynamics of the electrons.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"196 ","pages":"Article 114746"},"PeriodicalIF":5.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978643","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 : 2026-01-15DOI: 10.1016/j.optlastec.2026.114737
Yue Wu , Xiaoliang Liu , Canlin Jiang , Zhongxuan Lin , Xindong Deng , Bo Xiao , Huiying Xu , Zhiping Cai
A deep-red actively Q-switched fiber laser based on Ho3+-doped ZBLAN is experimentally demonstrated under 532 nm pumping using an acousto-optic modulator (AOM). The system achieves stable emission at 751 nm with pulse durations as short as 104 ns, pulse energies reaching 320 μJ, and peak powers up to 2.88 kW. Continuous wavelength tunability is implemented over an 8 nm spectral range (748.82–756.98 nm) via a Littman–Metcalf cavity configuration, demonstrating excellent spectral flexibility. At the central tuning wavelength of 752.4 nm, pulses as narrow as 111 ns are obtained while maintaining robust spectral and temporal stability. The effects of pump power, modulation frequency, and cavity parameters on pulse characteristics are systematically investigated. Rate-equation simulations with systematic sweeps of and agree well with the experiments and reproduce the measured pulse dynamics. This work illustrates the potential of high-peak-power, tunable deep-red fiber lasers using rare-earth-doped fluoride fibers, which enable wavelength-selective excitation schemes for spectroscopy and imaging.
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Pub Date : 2026-01-14DOI: 10.1016/j.optlastec.2026.114731
Elisabetta Avanzi , Giulia Maffeis , Nicola Serra , Alessandro Bossi , Valerio Gandolfi , Xinqiu Ye Lin , Andrea Farina , Cosimo D’Andrea , Laura Di Sieno , Paola Taroni , Antonio Pifferi , Alberto Dalla Mora
The multi-channel SiPM technology is a fascinating leverage for time-resolved diffuse optical spectroscopy thanks to its remarkable parallelization capability that leads to rapidly measuring absorption and scattering properties of a turbid medium at multiple positions across a wide spectral range (600–1000 nm) at high throughput.
For clinical applications, where the goal is to characterize the composition of biological tissues (e.g., fat, muscle, bone) in vivo non-invasively, these requirements are critical to support diagnosis with quantitative data, potentially reducing invasive procedures like biopsies and shortening waiting times for clinical exams.
Therefore, we developed a time domain diffuse optical spectroscopy (TD-DOS) system based on a compact 16-channel Silicon PhotoMultiplier (SiPM) array (footprint of 32 x 45 mm2, with single-photon timing resolution of 65 ps), capable of spectral or spatial parallelization. Spectral parallelization enables swift acquisition of extensive spectra, for example during functional tasks, allowing monitoring of task-related tissue changes and minimizing exam duration without compromising the informative content. Spatial parallelization facilitates tissue mapping or deep-layer investigation by leveraging the relationship between source-detector separation and penetration depth that holds when operating in the time domain.
In this work, our system was configured to parallelize wavelengths across the 700–950 nm range (spectral resolution Δλ = 16 nm) to match key absorption peaks of hemoglobin and lipids, and the rising edge of water (peaking at 975 nm). Performance was evaluated applying the MEDPHOT protocol on phantoms, showing excellent linearity (worst 0. 9973 for absorption and 0. 9833 for reduced scattering), minimal absorption–scattering coupling, and remarkable absorption accuracy (average error of 3 % on absolute values), though scattering was overestimated (average error of + 17 %). In vivo trials demonstrated excellent reproducibility (CV < 5 % for absorption and < 4.5 % for scattering over 20 repetitions) and effective characterization of tissue during scans of the back and calf, correlating well with complementary ultrasound information about fat, muscle and bone layering.
This system combines for the first time to our knowledge time domain insights, SiPM robustness, and parallelization speed, paving the way for efficient sample characterization in clinical and non-clinical contexts.
{"title":"Parallel high-throughput system for time domain diffuse optical spectroscopy based on a 16-channel SiPM array","authors":"Elisabetta Avanzi , Giulia Maffeis , Nicola Serra , Alessandro Bossi , Valerio Gandolfi , Xinqiu Ye Lin , Andrea Farina , Cosimo D’Andrea , Laura Di Sieno , Paola Taroni , Antonio Pifferi , Alberto Dalla Mora","doi":"10.1016/j.optlastec.2026.114731","DOIUrl":"10.1016/j.optlastec.2026.114731","url":null,"abstract":"<div><div>The multi-channel SiPM technology is a fascinating leverage for time-resolved diffuse optical spectroscopy thanks to its remarkable parallelization capability that leads to rapidly measuring absorption and scattering properties of a turbid medium at multiple positions across a wide spectral range (600–1000 nm) at high throughput.</div><div>For clinical applications, where the goal is to characterize the composition of biological tissues (<em>e.g.</em>, fat, muscle, bone) <em>in vivo</em> non-invasively, these requirements are critical to support diagnosis with quantitative data, potentially reducing invasive procedures like biopsies and shortening waiting times for clinical exams.</div><div>Therefore, we developed a time domain diffuse optical spectroscopy (TD-DOS) system based on a compact 16-channel Silicon PhotoMultiplier (SiPM) array (footprint of 32 x 45 mm<sup>2</sup>, with single-photon timing resolution of 65 ps), capable of spectral or spatial parallelization. Spectral parallelization enables swift acquisition of extensive spectra, for example during functional tasks, allowing monitoring of task-related tissue changes and minimizing exam duration without compromising the informative content. Spatial parallelization facilitates tissue mapping or deep-layer investigation by leveraging the relationship between source-detector separation and penetration depth that holds when operating in the time domain.</div><div>In this work, our system was configured to parallelize wavelengths across the 700–950 nm range (spectral resolution Δλ = 16 nm) to match key absorption peaks of hemoglobin and lipids, and the rising edge of water (peaking at 975 nm). Performance was evaluated applying the MEDPHOT protocol on phantoms, showing excellent linearity (worst <span><math><mrow><msup><mrow><mi>R</mi></mrow><mn>2</mn></msup><mo>=</mo></mrow></math></span>0. 9973 for absorption and <span><math><mrow><msup><mrow><mi>R</mi></mrow><mn>2</mn></msup><mo>=</mo></mrow></math></span> 0. 9833 for reduced scattering), minimal absorption–scattering coupling, and remarkable absorption accuracy (average error of 3 % on absolute values), though scattering was overestimated (average error of + 17 %). <em>In vivo</em> trials demonstrated excellent reproducibility (CV < 5 % for absorption and < 4.5 % for scattering over 20 repetitions) and effective characterization of tissue during scans of the back and calf, correlating well with complementary ultrasound information about fat, muscle and bone layering.</div><div>This system combines for the first time to our knowledge time domain insights, SiPM robustness, and parallelization speed, paving the way for efficient sample characterization in clinical and non-clinical contexts.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"196 ","pages":"Article 114731"},"PeriodicalIF":5.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978627","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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