Pub Date : 2026-02-06DOI: 10.1016/j.optlaseng.2026.109675
Yurong Li , Yi Zhou , Shikai Wu , Zhen Li , Jinsheng Zhang , Zhongquan Wen , Zhihai Zhang , Jing Xiang , Zhengguo Shang , GaoFeng Liang , Yin She , Gang Chen
Phase-contrast optical microscopy technology converts phase variations in transparent specimens into visible intensity variations and has played a pivotal role in the advancement of modern biomedicine. However, most research on phase-contrast microscopes is predominantly based on the Zernike phase-contrast microscope configuration, which employs conventional optics for sample illumination. Therefore, their resolution is fundamentally limited. To further improves the resolution, we propose a super-resolution phase-contrast technique that integrates a super-oscillation illuminating metalens with a phase-plate in a confocal microscope configuration. Experiments demonstrated the proposed super-resolution phase-contrast can resolve a phase-type grating with a linewidth of 120 nm, a pitch of 240 nm, and a phase difference of 0.5π, demonstrating a novel super-resolution phase-contrast microscopy modality. Our method holds great potential in probing nanoscale structures in transparent samples, such as cells and biomedical tissues.
{"title":"Phase-contrast super-resolution microscopy based on super-oscillation illumination","authors":"Yurong Li , Yi Zhou , Shikai Wu , Zhen Li , Jinsheng Zhang , Zhongquan Wen , Zhihai Zhang , Jing Xiang , Zhengguo Shang , GaoFeng Liang , Yin She , Gang Chen","doi":"10.1016/j.optlaseng.2026.109675","DOIUrl":"10.1016/j.optlaseng.2026.109675","url":null,"abstract":"<div><div>Phase-contrast optical microscopy technology converts phase variations in transparent specimens into visible intensity variations and has played a pivotal role in the advancement of modern biomedicine. However, most research on phase-contrast microscopes is predominantly based on the Zernike phase-contrast microscope configuration, which employs conventional optics for sample illumination. Therefore, their resolution is fundamentally limited. To further improves the resolution, we propose a super-resolution phase-contrast technique that integrates a super-oscillation illuminating metalens with a phase-plate in a confocal microscope configuration. Experiments demonstrated the proposed super-resolution phase-contrast can resolve a phase-type grating with a linewidth of 120 nm, a pitch of 240 nm, and a phase difference of 0.5π, demonstrating a novel super-resolution phase-contrast microscopy modality. Our method holds great potential in probing nanoscale structures in transparent samples, such as cells and biomedical tissues.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"201 ","pages":"Article 109675"},"PeriodicalIF":3.7,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.optlaseng.2026.109676
Guanghui Jing , Tingting Wu , Jian Wen , Pengju Cao , Wei Liu , Yulin Wang , Mengying Lu , Su Sheng , Chao Jiang
In fiber-optic sensing technology, the escalating demand for high-sensitivity detection of ultraviolet (UV) and blue light has emerged as a critical driver. To address this urgent need, this paper proposes a fiber-optic sensing structure based on MZI principle. The sensor adopts a fundamental SMF-FMF-SMF configuration fabricated via fiber fusion splicing technology. A tapering process is applied to the FMF segment to optimize its sensing performance. For further enhancement of the interferometer’s sensing sensitivity, inorganic perovskite CsPbBr3 is selected as the sensitive material and uniformly deposited on the surface of the tapered FMF segment using the dip-coating method. Experimental results show that the detection sensitivities of the sensor for ultraviolet light and blue light reach 284.41 pm/(mW·cm⁻²) and 75.84 pm/(mW·cm⁻²), respectively. In addition, the sensor exhibits prominent advantages such as excellent stability, anti-electromagnetic interference capability, compact structure, and simple preparation process. It is expected to be a highly competitive candidate in the field of dual-band detection for ultraviolet and blue light.
{"title":"All-inorganic perovskite CsPbBr₃-assisted Mach-Zehnder Interferometer (MZI) optical fiber sensor for highly sensitive ultraviolet and blue light detection","authors":"Guanghui Jing , Tingting Wu , Jian Wen , Pengju Cao , Wei Liu , Yulin Wang , Mengying Lu , Su Sheng , Chao Jiang","doi":"10.1016/j.optlaseng.2026.109676","DOIUrl":"10.1016/j.optlaseng.2026.109676","url":null,"abstract":"<div><div>In fiber-optic sensing technology, the escalating demand for high-sensitivity detection of ultraviolet (UV) and blue light has emerged as a critical driver. To address this urgent need, this paper proposes a fiber-optic sensing structure based on MZI principle. The sensor adopts a fundamental SMF-FMF-SMF configuration fabricated via fiber fusion splicing technology. A tapering process is applied to the FMF segment to optimize its sensing performance. For further enhancement of the interferometer’s sensing sensitivity, inorganic perovskite CsPbBr<sub>3</sub> is selected as the sensitive material and uniformly deposited on the surface of the tapered FMF segment using the dip-coating method. Experimental results show that the detection sensitivities of the sensor for ultraviolet light and blue light reach 284.41 pm/(mW·cm⁻²) and 75.84 pm/(mW·cm⁻²), respectively. In addition, the sensor exhibits prominent advantages such as excellent stability, anti-electromagnetic interference capability, compact structure, and simple preparation process. It is expected to be a highly competitive candidate in the field of dual-band detection for ultraviolet and blue light.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"201 ","pages":"Article 109676"},"PeriodicalIF":3.7,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-05DOI: 10.1016/j.optlaseng.2026.109672
Mengyao Li , Bingcai Liu , Jiaxin Meng , Kaixiang Xie , Hongjun Wang , Xueliang Zhu , Jintao Xu , Ailing Tian
In Frequency-Shifting Digital Holographic Microscopy (FSDHM), tilted illumination causes positional distortions in spectral sub-apertures, significantly reducing the accuracy of super-resolution phase reconstruction without precise correction. We propose a novel method for high-precision super-resolution phase reconstruction. By analyzing the complex amplitude distribution of the original image across spatial, fractional fourier, and fourier domains, a fractional - frequency domain position mapping model was established. We convert the spectral synthetic aperture problem into the fractional domain, thereby avoiding the limitations of indistinct spectral structural features. Exploiting spatial features of the original image in the fractional domain for feature extraction and matching, this method maps fractional domain offsets back to the frequency domain, enabling precise correction and synthesis of spectral sub-apertures. Simulations and experiments demonstrate sub-aperture positional distortion correction with errors below 1/4 pixel, improving accuracy by 72.9% over conventional FSDHM and achieving super-resolution phase reconstruction by a factor of 1.71. We confirm the method’s applicability to biological pathology samples. It significantly reduces reliance on mechanical control precision and supports flexible frequency-shifting operations with arbitrary offsets. We anticipate that our work offers a viable new tool for applications requiring the non-destructive evaluation of cells or pathological samples, as well as high-precision industrial inspection tasks.
{"title":"Toward accurate super-resolution reconstruction: Fractional - frequency domain position mapping model for digital holographic microscopy","authors":"Mengyao Li , Bingcai Liu , Jiaxin Meng , Kaixiang Xie , Hongjun Wang , Xueliang Zhu , Jintao Xu , Ailing Tian","doi":"10.1016/j.optlaseng.2026.109672","DOIUrl":"10.1016/j.optlaseng.2026.109672","url":null,"abstract":"<div><div>In Frequency-Shifting Digital Holographic Microscopy (FSDHM), tilted illumination causes positional distortions in spectral sub-apertures, significantly reducing the accuracy of super-resolution phase reconstruction without precise correction. We propose a novel method for high-precision super-resolution phase reconstruction. By analyzing the complex amplitude distribution of the original image across spatial, fractional fourier, and fourier domains, a fractional - frequency domain position mapping model was established. We convert the spectral synthetic aperture problem into the fractional domain, thereby avoiding the limitations of indistinct spectral structural features. Exploiting spatial features of the original image in the fractional domain for feature extraction and matching, this method maps fractional domain offsets back to the frequency domain, enabling precise correction and synthesis of spectral sub-apertures. Simulations and experiments demonstrate sub-aperture positional distortion correction with errors below 1/4 pixel, improving accuracy by 72.9% over conventional FSDHM and achieving super-resolution phase reconstruction by a factor of 1.71. We confirm the method’s applicability to biological pathology samples. It significantly reduces reliance on mechanical control precision and supports flexible frequency-shifting operations with arbitrary offsets. We anticipate that our work offers a viable new tool for applications requiring the non-destructive evaluation of cells or pathological samples, as well as high-precision industrial inspection tasks.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"201 ","pages":"Article 109672"},"PeriodicalIF":3.7,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.optlaseng.2026.109674
Yuqing Liu, Donghui Zheng, Lei Chen, Zhe Zhang
In phase-shifting interferometry using narrow-bandwidth light sources, ripple noise introduced by multiple error sources is one of the key factors limiting its wavefront calculation accuracy, this study proposed a generalized ripple suppression algorithm (GRSA) in its standard measurement scenarios. The distribution law of ripple errors caused by different error sources were investigated, and a mathematical model was established to decompose the wavefront shape components. The ripple components in wavefronts can be calculated and directly subtracted via two least-squares fittings on multiple wavefronts containing different ripple errors. Feasibility of the GRSA was verified through simulations and experiments, and the root mean square error of the simulated wavefront reaches 2.1 × 10−5λ. Factors affecting the accuracy of phase calculation and several special cases were analyzed, and optimization schemes for algorithm parameters were provided based on the analysis results. The experimental and simulation results show that the GRSA can effectively improve measurement accuracy and repeatability by suppressing the ripple error in the wavefront.
{"title":"Generalized ripple suppression algorithm for phase-shift interferometric wavefronts","authors":"Yuqing Liu, Donghui Zheng, Lei Chen, Zhe Zhang","doi":"10.1016/j.optlaseng.2026.109674","DOIUrl":"10.1016/j.optlaseng.2026.109674","url":null,"abstract":"<div><div>In phase-shifting interferometry using narrow-bandwidth light sources, ripple noise introduced by multiple error sources is one of the key factors limiting its wavefront calculation accuracy, this study proposed a generalized ripple suppression algorithm (GRSA) in its standard measurement scenarios. The distribution law of ripple errors caused by different error sources were investigated, and a mathematical model was established to decompose the wavefront shape components. The ripple components in wavefronts can be calculated and directly subtracted via two least-squares fittings on multiple wavefronts containing different ripple errors. Feasibility of the GRSA was verified through simulations and experiments, and the root mean square error of the simulated wavefront reaches 2.1 × 10<sup>−5</sup>λ. Factors affecting the accuracy of phase calculation and several special cases were analyzed, and optimization schemes for algorithm parameters were provided based on the analysis results. The experimental and simulation results show that the GRSA can effectively improve measurement accuracy and repeatability by suppressing the ripple error in the wavefront.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"201 ","pages":"Article 109674"},"PeriodicalIF":3.7,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optical microscopy is a pivotal technique for biomedical discovery, yet many high-performance instruments remain bulky and poorly suited for live-cell imaging and on-site computational analysis. This limits their accessibility and practical use in experiments requiring quantitative assessment of cellular dynamics. To address these challenges, we present a compact benchtop microscope that integrates an electrically tunable liquid lens (ETL), transport-of-intensity-equation (TIE)–based phase imaging, and edge-based artificial intelligence (AI) analysis within a single platform. A compact 2 × objective combined with an electrowetting ETL enables rapid, vibration-free axial defocus control with a measured magnification variation of 3.3 ± 0.2% over a 5.9 mm focal range, facilitating electronic acquisition of defocused intensity images required for TIE-based phase recovery. The 20 cm-tall modular system incorporates transparent heater–based environmental control for microfluidic cell culture and supports optional dual-channel fluorescence and wide-field imaging modules. For automated analysis, the microscope is coupled to an edge AI device that performs on-device cell segmentation, classification, and tracking from in-focus bright-field images using a convolutional neural network. By combining ETL-based electronic defocus, non-interferometric phase imaging, and edge-based bright-field image analysis in a compact form factor, the system provides label-free phase visualization alongside low-latency AI-assisted analysis, offering a practical and compact personal microscopy solution for research, education, and training applications.
{"title":"Electrically tunable benchtop microscope integrating TIE-based phase imaging and edge AI analysis","authors":"Hsieh-Fu Tsai , Soumyajit Podder , I-Ming Chang , Mao-Chang Ho","doi":"10.1016/j.optlaseng.2026.109659","DOIUrl":"10.1016/j.optlaseng.2026.109659","url":null,"abstract":"<div><div>Optical microscopy is a pivotal technique for biomedical discovery, yet many high-performance instruments remain bulky and poorly suited for live-cell imaging and on-site computational analysis. This limits their accessibility and practical use in experiments requiring quantitative assessment of cellular dynamics. To address these challenges, we present a compact benchtop microscope that integrates an electrically tunable liquid lens (ETL), transport-of-intensity-equation (TIE)–based phase imaging, and edge-based artificial intelligence (AI) analysis within a single platform. A compact 2 × objective combined with an electrowetting ETL enables rapid, vibration-free axial defocus control with a measured magnification variation of 3.3 ± 0.2% over a 5.9 mm focal range, facilitating electronic acquisition of defocused intensity images required for TIE-based phase recovery. The 20 cm-tall modular system incorporates transparent heater–based environmental control for microfluidic cell culture and supports optional dual-channel fluorescence and wide-field imaging modules. For automated analysis, the microscope is coupled to an edge AI device that performs on-device cell segmentation, classification, and tracking from in-focus bright-field images using a convolutional neural network. By combining ETL-based electronic defocus, non-interferometric phase imaging, and edge-based bright-field image analysis in a compact form factor, the system provides label-free phase visualization alongside low-latency AI-assisted analysis, offering a practical and compact personal microscopy solution for research, education, and training applications.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"201 ","pages":"Article 109659"},"PeriodicalIF":3.7,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-03DOI: 10.1016/j.optlaseng.2026.109665
Aswathi K Sivarajan, Harsh Vardhan, Sakshi Choudhary, Salla Gangi Reddy, Ravi Kumar
Perfect Optical Vortex (POV) beams have gained significant attention due to their ability to maintain a constant ring size with increasing topological charge (TC). This property of the POV beam helps to attain a vortex beam with large TC and controllable ring size simultaneously. In this paper, we propose a new simple way to generate twin ring POV (TR-POV) beam by introducing a conical phase into the Bessel phase function. In TR-POV, we can precisely control the transverse cross-section profile, where the ring radius, ring width, and TC of both rings can be assigned arbitrarily, depending on the application. We have experimentally generated these beams and studied their detailed propagation characteristics in free space. Through the interferometric analysis, we have also determined the TCs correspond to both the rings. We believe that the proposed beams can have profound application in various optical domains, such as microscopy, imaging through turbid media, communication, security etc.
{"title":"Tunable twin-ring perfect optical vortex beams and their propagation characteristics","authors":"Aswathi K Sivarajan, Harsh Vardhan, Sakshi Choudhary, Salla Gangi Reddy, Ravi Kumar","doi":"10.1016/j.optlaseng.2026.109665","DOIUrl":"10.1016/j.optlaseng.2026.109665","url":null,"abstract":"<div><div>Perfect Optical Vortex (POV) beams have gained significant attention due to their ability to maintain a constant ring size with increasing topological charge (TC). This property of the POV beam helps to attain a vortex beam with large TC and controllable ring size simultaneously. In this paper, we propose a new simple way to generate twin ring POV (TR-POV) beam by introducing a conical phase into the Bessel phase function. In TR-POV, we can precisely control the transverse cross-section profile, where the ring radius, ring width, and TC of both rings can be assigned arbitrarily, depending on the application. We have experimentally generated these beams and studied their detailed propagation characteristics in free space. Through the interferometric analysis, we have also determined the TCs correspond to both the rings. We believe that the proposed beams can have profound application in various optical domains, such as microscopy, imaging through turbid media, communication, security etc.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"201 ","pages":"Article 109665"},"PeriodicalIF":3.7,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-02DOI: 10.1016/j.optlaseng.2026.109669
Yunmei Jiao , Huifeng Wang , Hao Du , Yuanhe Shan , Zefeng Pan , Chengyan Zhang , He Huang
Visual inspection of underwater infrastructure is severely hampered by image degradation from light scattering in turbid media, which obscures critical surface defects. To address this engineering challenge, this paper proposes a robust visual enhancement method based on polarization imaging. The proposed framework operates through two primary stages. The first stage involves physical parameter estimation, where a DoP-Guided Hierarchical Quadtree Background Light Estimation (DHQBLE) technique is developed, and scene depth is robustly estimated by jointly optimizing the red channel prior, the Polarization Gradient Direction Field (PGDF), and multi-channel attenuation differences. The second stage focuses on adaptive feature fusion, implemented through a Multi-scale Decomposition Fusion with Contrast Consistency (MDF-CC) framework that adaptively integrates intensity and polarization features to enhance image contrast and restore fine structural details. Comprehensive experiments were conducted on self-built and real-world underwater datasets, encompassing various defect types (cracks, holes, spalling) and environmental conditions (turbidity: 1.78–5.39 g/L; flow velocity: 2.65–4.42 m/s). The results demonstrate that the proposed method consistently outperforms state-of-the-art approaches, achieving superior quantitative (PSNR, SSIM, contrast, entropy) and qualitative performance. This confirms its effectiveness as a robust solution for high-fidelity optical inspection in complex underwater environments.
{"title":"Robust polarimetric image restoration for underwater concrete defect inspection in turbid environments","authors":"Yunmei Jiao , Huifeng Wang , Hao Du , Yuanhe Shan , Zefeng Pan , Chengyan Zhang , He Huang","doi":"10.1016/j.optlaseng.2026.109669","DOIUrl":"10.1016/j.optlaseng.2026.109669","url":null,"abstract":"<div><div>Visual inspection of underwater infrastructure is severely hampered by image degradation from light scattering in turbid media, which obscures critical surface defects. To address this engineering challenge, this paper proposes a robust visual enhancement method based on polarization imaging. The proposed framework operates through two primary stages. The first stage involves physical parameter estimation, where a DoP-Guided Hierarchical Quadtree Background Light Estimation (DHQBLE) technique is developed, and scene depth is robustly estimated by jointly optimizing the red channel prior, the Polarization Gradient Direction Field (PGDF), and multi-channel attenuation differences. The second stage focuses on adaptive feature fusion, implemented through a Multi-scale Decomposition Fusion with Contrast Consistency (MDF-CC) framework that adaptively integrates intensity and polarization features to enhance image contrast and restore fine structural details. Comprehensive experiments were conducted on self-built and real-world underwater datasets, encompassing various defect types (cracks, holes, spalling) and environmental conditions (turbidity: 1.78–5.39 g/L; flow velocity: 2.65–4.42 m/s). The results demonstrate that the proposed method consistently outperforms state-of-the-art approaches, achieving superior quantitative (PSNR, SSIM, contrast, entropy) and qualitative performance. This confirms its effectiveness as a robust solution for high-fidelity optical inspection in complex underwater environments.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"201 ","pages":"Article 109669"},"PeriodicalIF":3.7,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-02DOI: 10.1016/j.optlaseng.2026.109666
Lucas Person , Théo Sentagne , Raphaël Fouque , Robin Bouclier , John-Eric Dufour , Jean-Charles Passieux , Jean-Noël Périé
Digital Image Correlation typically involves deforming a pixelated image in order to compare its grey levels with those of another image. To achieve sub-pixel accuracy, grey-level interpolation is required. However, this interpolation is non-physical and introduces biases that become particularly detrimental under finite strains. In this work, we propose an alternative photometric approach that entirely avoids interpolation, grounded in a rigorous formulation of the direct image formation problem. The inverse problem is then posed as the joint estimation of a super-resolved digital twin—representing the scene and sensor characteristics—and the displacement fields. Both are estimated by minimising a single cost function that compares all available real images to their synthetic counterparts generated through a physically based rendering model. This minimisation is performed using an efficient alternating minimisation scheme. Several two-dimensional test cases are analysed, demonstrating that the proposed method is effectively unbiased and exhibits significantly lower uncertainties than state-of-the-art DIC techniques.
{"title":"A Photometric approach to Digital Image Correlation with a Super-Resolved digital twin (SR-PhDIC)","authors":"Lucas Person , Théo Sentagne , Raphaël Fouque , Robin Bouclier , John-Eric Dufour , Jean-Charles Passieux , Jean-Noël Périé","doi":"10.1016/j.optlaseng.2026.109666","DOIUrl":"10.1016/j.optlaseng.2026.109666","url":null,"abstract":"<div><div>Digital Image Correlation typically involves deforming a pixelated image in order to compare its grey levels with those of another image. To achieve sub-pixel accuracy, grey-level interpolation is required. However, this interpolation is non-physical and introduces biases that become particularly detrimental under finite strains. In this work, we propose an alternative photometric approach that entirely avoids interpolation, grounded in a rigorous formulation of the direct image formation problem. The inverse problem is then posed as the joint estimation of a super-resolved digital twin—representing the scene and sensor characteristics—and the displacement fields. Both are estimated by minimising a single cost function that compares all available real images to their synthetic counterparts generated through a physically based rendering model. This minimisation is performed using an efficient alternating minimisation scheme. Several two-dimensional test cases are analysed, demonstrating that the proposed method is effectively unbiased and exhibits significantly lower uncertainties than state-of-the-art DIC techniques.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"201 ","pages":"Article 109666"},"PeriodicalIF":3.7,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-02DOI: 10.1016/j.optlaseng.2026.109625
Win Indra , Irianto , Jamil Abedalrahim Jamil Alsayaydeh , Adam Wong Yoon Khang , Nurulhalim Bin Hassim , Safarudin Gazali Herawan
We demonstrate a low-cost, stable, and tunable laser system by phase-locking a commercial telecom-grade tunable laser (ITLA) to an Optical Frequency Comb (OFC) within the C-band. Using minimal optical hardware and sub-mW OFC power, we achieved short-term integrated phase noise of 10 mrad and long-term frequency stability of ±0.01 Hz over 10 h. This system enables scalable, OFC-locked tunable lasers and holds promise for applications like tunable THz wave generation and comb-locked transmitters in DWDM systems, supporting scalable phase-locking of multiple lasers with OFC power in the nW regime, making it highly adaptable for various OFC generators.
{"title":"Towards low-noise tunable terahertz waves generation via photomixing","authors":"Win Indra , Irianto , Jamil Abedalrahim Jamil Alsayaydeh , Adam Wong Yoon Khang , Nurulhalim Bin Hassim , Safarudin Gazali Herawan","doi":"10.1016/j.optlaseng.2026.109625","DOIUrl":"10.1016/j.optlaseng.2026.109625","url":null,"abstract":"<div><div>We demonstrate a low-cost, stable, and tunable laser system by phase-locking a commercial telecom-grade tunable laser (ITLA) to an Optical Frequency Comb (OFC) within the C-band. Using minimal optical hardware and sub-mW OFC power, we achieved short-term integrated phase noise of 10 mrad and long-term frequency stability of ±0.01 Hz over 10 h. This system enables scalable, OFC-locked tunable lasers and holds promise for applications like tunable THz wave generation and comb-locked transmitters in DWDM systems, supporting scalable phase-locking of multiple lasers with OFC power in the nW regime, making it highly adaptable for various OFC generators.</div></div>","PeriodicalId":49719,"journal":{"name":"Optics and Lasers in Engineering","volume":"201 ","pages":"Article 109625"},"PeriodicalIF":3.7,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-02DOI: 10.1016/j.optlaseng.2026.109670
Yujun Ma , Xueshi Zhang , Yesheng Wang , Fusheng Li , Qiuyi Han , Shanduan Zhang
Laser-generated plasma (LGP) light sources are critical for high-resolution bright field inspection of modern semiconductor wafer defects. This paper presents a 12 kW LGP system to enhance plasma radiance, employing reflective focusing with a low F-number to suppress plasma elongation. All optics are housed in a sealed chamber for operational safety. A novel alignment method is introduced to achieve precise optical alignment within the sealed chamber. This method uses a metal sphere to regularize the spot image and calculates component offset through image processing. The principle is analytically derived and verified via ray-tracing simulations, achieving a theoretical alignment accuracy of 0.01 mm. Experimental results demonstrate the robustness of the method: realignment consistently converged within 30 iterations across multiple disassembly-reassembly cycles. Moreover, a quantitative study reveals a clear decrease in output power as the offset of the optical axis increases. At a pump laser power of 6.0 kW, the system achieved an average output power of 315.8 W, with <0.4% variation over repeated cycles. This work provides a reliable, operator-independent alignment solution to ensure optimal performance of high-power LGP light sources.
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