Pub Date : 2026-02-05DOI: 10.1016/j.optlastec.2026.114820
Jiachen Guo , Benyu Zhang , Zhifang Xu , Lina Bi , Shuang Li , Yueyan Shi , Liang Zhou , Shiqing Zhou , Jiaqi Zhang
This work presents an experimental demonstration of a high-sensitivity optical fiber sensor based on a calcium alginate (CaAlg)-functionalized single mode–tapered multimode–single mode (STMS) structure for humidity and pressure monitoring. By employing a tapered multimode fiber (TMF) to enhance the interaction with the evanescent field and integrating a biocompatible CaAlg film with excellent hygroscopic properties, the sensor achieves high sensitivity for detecting both humidity and pressure. The sensor demonstrates a humidity sensitivity of 0.315 dBm/%RH in optical power and 0.225 nm/%RH in wavelength shift over the 30 %–70 % RH range, with response and recovery times of 0.42 s and 0.2 s, respectively. For pressure sensing, the sensor exhibits an ultra-high sensitivity of 91.48 dBm/kPa within the 0–0.25 kPa range. Additionally, the sensor was tested at 50 % and 70 % RH for 120 min, with standard deviations of 0.2622 and 0.6327, respectively. The relative error at most only 0.0067 indicating the sensor’s high repeatability and reliability. The fabrication process is simple, environmentally friendly, and suitable for health monitoring applications. This work presents a promising approach for the development of multifunctional, miniaturized, and high-resolution fiber-optic sensors, with potential applications in wearable devices, healthcare monitoring, and soft robotics.
{"title":"High-performance humidity and pressure sensor based on STMS fiber structure coated with Ca-alginate hydrogel","authors":"Jiachen Guo , Benyu Zhang , Zhifang Xu , Lina Bi , Shuang Li , Yueyan Shi , Liang Zhou , Shiqing Zhou , Jiaqi Zhang","doi":"10.1016/j.optlastec.2026.114820","DOIUrl":"10.1016/j.optlastec.2026.114820","url":null,"abstract":"<div><div>This work presents an experimental demonstration of a high-sensitivity optical fiber sensor based on a calcium alginate (CaAlg)-functionalized single mode–tapered multimode–single mode (STMS) structure for humidity and pressure monitoring. By employing a tapered multimode fiber (TMF) to enhance the interaction with the evanescent field and integrating a biocompatible CaAlg film with excellent hygroscopic properties, the sensor achieves high sensitivity for detecting both humidity and pressure. The sensor demonstrates a humidity sensitivity of 0.315 dBm/%RH in optical power and 0.225 nm/%RH in wavelength shift over the 30 %–70 % RH range, with response and recovery times of 0.42 s and 0.2 s, respectively. For pressure sensing, the sensor exhibits an ultra-high sensitivity of 91.48 dBm/kPa within the 0–0.25 kPa range. Additionally, the sensor was tested at 50 % and 70 % RH for 120 min, with standard deviations of 0.2622 and 0.6327, respectively. The relative error at most only 0.0067 indicating the sensor’s high repeatability and reliability. The fabrication process is simple, environmentally friendly, and suitable for health monitoring applications. This work presents a promising approach for the development of multifunctional, miniaturized, and high-resolution fiber-optic sensors, with potential applications in wearable devices, healthcare monitoring, and soft robotics.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"198 ","pages":"Article 114820"},"PeriodicalIF":5.0,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116768","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 : 2026-02-05DOI: 10.1016/j.optlastec.2026.114879
Ping Huang , Guanghui Zhang , Zhichuang Chen , Xinping He , Qingan Lu , Yuxing Huang , Hui Jiao , Tanggao Feng , Yuhong Long
Owing to the high thermal sensitivity of NdFeB, simultaneously achieving a high material removal rate (MRR) and a low heat-affected zone (HAZ) remains challenging. This study employs water-jet-guided laser (WJGL) machining and develops an integrated hot–cold thermal balance control framework that couples multiphysics simulation, a data-driven surrogate model, and multi-objective optimization. The simulations reveal a V-shaped surface water-flow profile: intensified convection at the periphery suppresses thermal diffusion, while the core region—experiencing relatively low flow velocity—maintains temperatures near the vaporization threshold to sustain efficient ablation, thereby enabling spatially coordinated hot–cold regulation. A small-sample surrogate based on Gaussian process regression is combined with NSGA-II to compute the Pareto front, yielding a representative optimum with HAZ of 39.79 μm and MRR of 3.44 mm2 s⁻1. Temperature-field analysis confirms that this parameter set preserves near-threshold vaporization in the core to secure efficiency, while constraining lateral thermal spread. The proposed approach provides a rigorous pathway for the coordinated optimization of low thermal damage and high efficiency in WJGL machining of thermally sensitive materials.
{"title":"Mechanisms of Hot–Cold thermal balance control in Water-Jet-Guided laser machining of NdFeB permanent magnets","authors":"Ping Huang , Guanghui Zhang , Zhichuang Chen , Xinping He , Qingan Lu , Yuxing Huang , Hui Jiao , Tanggao Feng , Yuhong Long","doi":"10.1016/j.optlastec.2026.114879","DOIUrl":"10.1016/j.optlastec.2026.114879","url":null,"abstract":"<div><div>Owing to the high thermal sensitivity of NdFeB, simultaneously achieving a high material removal rate (MRR) and a low heat-affected zone (HAZ) remains challenging. This study employs water-jet-guided laser (WJGL) machining and develops an integrated hot–cold thermal balance control framework that couples multiphysics simulation, a data-driven surrogate model, and multi-objective optimization. The simulations reveal a V-shaped surface water-flow profile: intensified convection at the periphery suppresses thermal diffusion, while the core region—experiencing relatively low flow velocity—maintains temperatures near the vaporization threshold to sustain efficient ablation, thereby enabling spatially coordinated hot–cold regulation. A small-sample surrogate based on Gaussian process regression is combined with NSGA-II to compute the Pareto front, yielding a representative optimum with HAZ of 39.79 μm and MRR of 3.44 mm<sup>2</sup> s⁻<sup>1</sup>. Temperature-field analysis confirms that this parameter set preserves near-threshold vaporization in the core to secure efficiency, while constraining lateral thermal spread. The proposed approach provides a rigorous pathway for the coordinated optimization of low thermal damage and high efficiency in WJGL machining of thermally sensitive materials.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"198 ","pages":"Article 114879"},"PeriodicalIF":5.0,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116769","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}
Based on the advection flow combustion platform, this study conducted laser ignition experiments on NH3/H2/Air premixed gases under different equivalence ratios (ϕ) and hydrogen blending ratios (α) with the velocity of 1 m/s, analyzing key results such as minimum ignition energy (MIE), flame development area, flame front velocity, and flame centroid. To enhance the optical relevance of this study, a precisely controlled Q-switched Nd:YAG laser system and high-speed optical diagnostics were employed to characterize the ignition process and intrinsic flame luminosity. The results demonstrate that increasing the α effectively reduces MIE, with this effect being more pronounced in lean mixtures. As the α increases, the ϕ corresponding to the minimum MIE shifts toward leaner conditions. Richer mixtures with higher hydrogen blending ratios significantly accelerate flame development, resulting in greater maximum flame areas and flame front velocities. However, excessively high hydrogen blending ratios can induce flame oscillation, altering the flow state in the combustion chamber and causing random variations in combustion parameters. This study further reveals, through optical measurements, that these oscillations are accompanied by fluctuations in flame morphology and luminous intensity, indicating a coupling between optical emission characteristics and unsteady combustion. The formation and development of the third-lobe flame kernel during laser ignition influence the initial trend of the flame centroid and hydrogen blending effectively mitigates the upward movement of ammonia flames, particularly in lean mixtures, although this improvement diminishes as the α continues to increase in this platform. Changes in MIE, flame front velocity, and flame centroid indicate that the benefits of hydrogen addition are more pronounced in leaner mixtures, to ensure both stable laser ignition and efficient combustion, this study recommends limiting the hydrogen blending ratio in advective NH3/H2/Air mixtures to no more than 10 % in advective flow combustion platform.
{"title":"Laser-induced plasma ignition and combustion characteristics for advective NH3/H2/Air mixtures with constant velocity","authors":"Junjie Zhang, Erjiang Hu, Zihao Chen, Geyuan Yin, Zuohua Huang","doi":"10.1016/j.optlastec.2026.114877","DOIUrl":"10.1016/j.optlastec.2026.114877","url":null,"abstract":"<div><div>Based on the advection flow combustion platform, this study conducted laser ignition experiments on NH<sub>3</sub>/H<sub>2</sub>/Air premixed gases under different equivalence ratios (<em>ϕ</em>) and hydrogen blending ratios (<em>α</em>) with the velocity of 1 m/s, analyzing key results such as minimum ignition energy (MIE), flame development area, flame front velocity, and flame centroid. To enhance the optical relevance of this study, a precisely controlled Q-switched Nd:YAG laser system and high-speed optical diagnostics were employed to characterize the ignition process and intrinsic flame luminosity. The results demonstrate that increasing the <em>α</em> effectively reduces MIE, with this effect being more pronounced in lean mixtures. As the <em>α</em> increases, the <em>ϕ</em> corresponding to the minimum MIE shifts toward leaner conditions. Richer mixtures with higher hydrogen blending ratios significantly accelerate flame development, resulting in greater maximum flame areas and flame front velocities. However, excessively high hydrogen blending ratios can induce flame oscillation, altering the flow state in the combustion chamber and causing random variations in combustion parameters. This study further reveals, through optical measurements, that these oscillations are accompanied by fluctuations in flame morphology and luminous intensity, indicating a coupling between optical emission characteristics and unsteady combustion. The formation and development of the third-lobe flame kernel during laser ignition influence the initial trend of the flame centroid and hydrogen blending effectively mitigates the upward movement of ammonia flames, particularly in lean mixtures, although this improvement diminishes as the <em>α</em> continues to increase in this platform. Changes in MIE, flame front velocity, and flame centroid indicate that the benefits of hydrogen addition are more pronounced in leaner mixtures, to ensure both stable laser ignition and efficient combustion, this study recommends limiting the hydrogen blending ratio in advective NH<sub>3</sub>/H<sub>2</sub>/Air mixtures to no more than 10 % in advective flow combustion platform.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"198 ","pages":"Article 114877"},"PeriodicalIF":5.0,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116345","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 : 2026-02-04DOI: 10.1016/j.optlastec.2026.114868
Wei Guo, Jifei Ye, Hao Chang, Chenghao Yu, Sai Li, Hongjie Kong
This study investigates the effects of pulsed laser irradiation (532 nm and 1064 nm) on the performance of GaInP/GaAs/Ge triple-junction solar cells and their subcells. The analysis was conducted through electroluminescence (EL) characterization and electrical performance testing. The results reveal that lasers of different wavelengths induce distinct damage patterns in the multi-junction solar cells. The unique spectral response characteristics of each subcell cause this effect. The 532 nm laser is primarily absorbed by the GaInP top cell, leading to its initial performance degradation and influence on red-light emission capability. The 1064 nm laser penetrates to the GaInP top cell, directly damaging the GaAs and Ge layers, which causes their performance to decline and influences the infrared light emission capability. As the laser energy density increases, the extent of cell damage intensifies, and the subcells lose their luminescence and photoelectric conversion capabilities. This research reveals the wavelength-dependent damage mechanisms of lasers in multi-junction solar cells. It provides a reference for the reliability assessment and protective design of solar cells for space applications.
{"title":"Performance analysis of Laser-Ablated Triple-Junction solar cells using spectral response properties","authors":"Wei Guo, Jifei Ye, Hao Chang, Chenghao Yu, Sai Li, Hongjie Kong","doi":"10.1016/j.optlastec.2026.114868","DOIUrl":"10.1016/j.optlastec.2026.114868","url":null,"abstract":"<div><div>This study investigates the effects of pulsed laser irradiation (532 nm and 1064 nm) on the performance of GaInP/GaAs/Ge triple-junction solar cells and their subcells. The analysis was conducted through electroluminescence (EL) characterization and electrical performance testing. The results reveal that lasers of different wavelengths induce distinct damage patterns in the multi-junction solar cells. The unique spectral response characteristics of each subcell cause this effect. The 532 nm laser is primarily absorbed by the GaInP top cell, leading to its initial performance degradation and influence on red-light emission capability. The 1064 nm laser penetrates to the GaInP top cell, directly damaging the GaAs and Ge layers, which causes their performance to decline and influences the infrared light emission capability. As the laser energy density increases, the extent of cell damage intensifies, and the subcells lose their luminescence and photoelectric conversion capabilities. This research reveals the wavelength-dependent damage mechanisms of lasers in multi-junction solar cells. It provides a reference for the reliability assessment and protective design of solar cells for space applications.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"198 ","pages":"Article 114868"},"PeriodicalIF":5.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116766","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 : 2026-02-04DOI: 10.1016/j.optlastec.2026.114815
Yanqiu Zhao , Tingyan Yan , Rui Li , Jiangfeng Wang , Chao Ma , Xiaohong Zhan
Dual laser beam bilateral synchronous welding (DLBSW) has been proven as an effective fabrication technique for Ti-6Al-4V alloy T-joints. Nevertheless, the pronounced impact of gravity deflection on fluid flow and keyhole stability in DLBSW of spatially complex curved structures must be thoroughly evaluated, given its consequential effects on porosity and fatigue life. In this paper, the thermal-fluid coupling models of Ti-6Al-4V alloy T-joints during horizontal DLBSW and Non-Horizontal DLBSW at the gravity deflection angle (θ) of 25° and 40° were respectively established. The spatiotemporal characteristics of fluid flow under diverse gravitational regimes and the dynamic evolution of the keyhole were comprehensively delineated. Additionally, the fundamental mechanism governing gravity-driven distortion of the molten pool and the resultant destabilization of the orifice under the dual-beam coupling effect was uncovered. It is revealed that gravitational deflection induces a reconfiguration of liquid metal flow from the upper molten pool, leading to diminished thermal energy delivery to the anterior wall. This, in turn, restricts the advancement of the solid/liquid interface and exacerbates thermal asymmetry. Moreover, gravitational deflection enhances bubble nucleation, impedes their removal, and compromises the liquid’s void-filling efficacy, culminating in porosity formation. These outcomes offer significant guidance for porosity suppression strategies and inform the refinement of DLBSW techniques for T-joint manufacturing.
{"title":"Gravity-induced distortion dynamics of molten pool and keyhole during non-horizontal dual laser beam bilateral synchronous welding for Ti-6Al-4V alloy T-joints","authors":"Yanqiu Zhao , Tingyan Yan , Rui Li , Jiangfeng Wang , Chao Ma , Xiaohong Zhan","doi":"10.1016/j.optlastec.2026.114815","DOIUrl":"10.1016/j.optlastec.2026.114815","url":null,"abstract":"<div><div>Dual laser beam bilateral synchronous welding (DLBSW) has been proven as an effective fabrication technique for Ti-6Al-4V alloy T-joints. Nevertheless, the pronounced impact of gravity deflection on fluid flow and keyhole stability in DLBSW of spatially complex curved structures must be thoroughly evaluated, given its consequential effects on porosity and fatigue life. In this paper, the thermal-fluid coupling models of Ti-6Al-4V alloy T-joints during horizontal DLBSW and Non-Horizontal DLBSW at the gravity deflection angle (θ) of 25° and 40° were respectively established. The spatiotemporal characteristics of fluid flow under diverse gravitational regimes and the dynamic evolution of the keyhole were comprehensively delineated. Additionally, the fundamental mechanism governing gravity-driven distortion of the molten pool and the resultant destabilization of the orifice under the dual-beam coupling effect was uncovered. It is revealed that gravitational deflection induces a reconfiguration of liquid metal flow from the upper molten pool, leading to diminished thermal energy delivery to the anterior wall. This, in turn, restricts the advancement of the solid/liquid interface and exacerbates thermal asymmetry. Moreover, gravitational deflection enhances bubble nucleation, impedes their removal, and compromises the liquid’s void-filling efficacy, culminating in porosity formation. These outcomes offer significant guidance for porosity suppression strategies and inform the refinement of DLBSW techniques for T-joint manufacturing.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"198 ","pages":"Article 114815"},"PeriodicalIF":5.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116764","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}
In the ultrafast laser stealth dicing of silicon carbide wafers, achieving both high efficiency and superior quality remains a significant challenge in wafer manufacturing. To address this, this study innovatively proposes applying laser power modulation to multi-layer modified stealth dicing of 4H-SiC, aiming to enhance cross-section quality while maintaining processing efficiency. Experiments reveal that multi-layer modification dicing utilizing self-focusing effects achieves over fourfold efficiency gains compared to single-layer modification, yet results in significantly increased cross-section roughness. Molecular dynamics simulations reveal that this phenomenon stems from edge thermal stress concentration caused by uneven heat dissipation. Building upon this insight, the proposed laser power modulation technique achieves a substantial reduction in cross-section roughness under optimized parameters, thereby synergistically enhancing both efficiency and quality. This study offers valuable insights and practical methodologies for high-quality and high-efficiency SiC wafer stealth dicing.
{"title":"Study on picosecond laser multi-layer modification and stealth dicing of 4H-SiC wafers based on laser power modulation","authors":"Yixiong Yan , Sijia Chen , Yuxuan Cheng , Cong Mao , Mingjun Zhang , Yu Zheng , Weidong Tang , Ji’an Duan","doi":"10.1016/j.optlastec.2026.114882","DOIUrl":"10.1016/j.optlastec.2026.114882","url":null,"abstract":"<div><div>In the ultrafast laser stealth dicing of silicon carbide wafers, achieving both high efficiency and superior quality remains a significant challenge in wafer manufacturing. To address this, this study innovatively proposes applying laser power modulation to multi-layer modified stealth dicing of 4H-SiC, aiming to enhance cross-section quality while maintaining processing efficiency. Experiments reveal that multi-layer modification dicing utilizing self-focusing effects achieves over fourfold efficiency gains compared to single-layer modification, yet results in significantly increased cross-section roughness. Molecular dynamics simulations reveal that this phenomenon stems from edge thermal stress concentration caused by uneven heat dissipation. Building upon this insight, the proposed laser power modulation technique achieves a substantial reduction in cross-section roughness under optimized parameters, thereby synergistically enhancing both efficiency and quality. This study offers valuable insights and practical methodologies for high-quality and high-efficiency SiC wafer stealth dicing.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"198 ","pages":"Article 114882"},"PeriodicalIF":5.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116767","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 : 2026-02-04DOI: 10.1016/j.optlastec.2026.114761
Yizheng Sun , Weiming Zeng , Hengwei Shen , Tongyu Yao , He Yan , Yushan Chen , Wen Chen , Jing Liu , Zhichun Fan
Glass-to-metal (GTM) seals are essential in Electrical Penetration Assemblies (EPAs) of nuclear power plants, where long-term hermeticity relies on residual stress generated by thermal expansion mismatch (Δα). However, conventional models cannot capture the thermo-mechanical interactions and uneven residual stress fields that often induce sealing failure, making accurate prediction and monitoring a major challenge. In this study, a thermo-mechanical analytical framework incorporating interface shear–normal stress coupling, finite element modeling, and embedded fiber Bragg grating arrays was combined to achieve real-time three-dimensional strain monitoring during manufacturing and service processes. Results demonstrate that a controlled positive Δα (8.46–12.73 × 10−6 K−1) yields stable compressive stresses, whereas negative or insufficient Δα induces cracking or hermetic degradation. Furthermore, thermal cycling experiments revealed progressive residual stress relaxation and structural stabilization of the glass. These findings provide practical guidelines for improving the sealing reliability of nuclear EPAs and offer a transferable methodology for other high-temperature thermo-mechanical structures.
{"title":"Thermo-mechanical coupling in electrical penetration assembly: residual strain analysis with embedded FBG strain monitoring","authors":"Yizheng Sun , Weiming Zeng , Hengwei Shen , Tongyu Yao , He Yan , Yushan Chen , Wen Chen , Jing Liu , Zhichun Fan","doi":"10.1016/j.optlastec.2026.114761","DOIUrl":"10.1016/j.optlastec.2026.114761","url":null,"abstract":"<div><div>Glass-to-metal (GTM) seals are essential in Electrical Penetration Assemblies (EPAs) of nuclear power plants, where long-term hermeticity relies on residual stress generated by thermal expansion mismatch (Δ<em>α</em>). However, conventional models cannot capture the thermo-mechanical interactions and uneven residual stress fields that often induce sealing failure, making accurate prediction and monitoring a major challenge. In this study, a thermo-mechanical analytical framework incorporating interface shear–normal stress coupling, finite element modeling, and embedded fiber Bragg grating arrays was combined to achieve real-time three-dimensional strain monitoring during manufacturing and service processes. Results demonstrate that a controlled positive Δ<em>α</em> (8.46–12.73 × 10<sup>−6</sup> K<sup>−1</sup>) yields stable compressive stresses, whereas negative or insufficient Δ<em>α</em> induces cracking or hermetic degradation. Furthermore, thermal cycling experiments revealed progressive residual stress relaxation and structural stabilization of the glass. These findings provide practical guidelines for improving the sealing reliability of nuclear EPAs and offer a transferable methodology for other high-temperature thermo-mechanical structures.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"198 ","pages":"Article 114761"},"PeriodicalIF":5.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116762","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 : 2026-02-04DOI: 10.1016/j.optlastec.2026.114876
Wangfan Zhou , Tao Wang , Jun Chen , Haoyu Zhou , Gui Zhang , Enoch Asuako Larson , Yu Yang
Adhesive repair is essential for restoring the structural integrity and mechanical performance of carbon fiber reinforced polymer (CFRP) components. After extended service, repaired structures require the removal of the adhesive patches for secondary repair. This paper investigates the interfacial damage of CFRP bonded components under laser-induced shock waves. The results show that the damage of CFRP bonding interface under laser-induced shock wave is due to the local tensile stress exceeding the tensile strength of the interface. The magnitude of local tensile stress depends on the superposition of incident wave and reflected wave at the bonding interface. Increasing pulse energy and spot diameter intensifies damage at the adhesive interface and reduces the interfacial tensile strength. As CFRP thickness increases, the interlayer tensile stress decreases, and the bonding interface damage is correspondingly reduced. Increasing curvature enlarges the angle between the reflected and incident stress wave at the bonding interface and the back surface, resulting in the reduction of the damage. Applying a metallic constraint to the rear surface of the specimen reduces the magnitude of the reflected tensile stress, thereby mitigating interfacial damage. Conversely, when the rear surface is unconstrained, the reflected tensile stress is higher, resulting in more pronounced interfacial damage.
{"title":"Delamination mechanism of CFRP adhesive layer under laser-induced shock waves","authors":"Wangfan Zhou , Tao Wang , Jun Chen , Haoyu Zhou , Gui Zhang , Enoch Asuako Larson , Yu Yang","doi":"10.1016/j.optlastec.2026.114876","DOIUrl":"10.1016/j.optlastec.2026.114876","url":null,"abstract":"<div><div>Adhesive repair is essential for restoring the structural integrity and mechanical performance of carbon fiber reinforced polymer (CFRP) components. After extended service, repaired structures require the removal of the adhesive patches for secondary repair. This paper investigates the interfacial damage of CFRP bonded components under laser-induced shock waves. The results show that the damage of CFRP bonding interface under laser-induced shock wave is due to the local tensile stress exceeding the tensile strength of the interface. The magnitude of local tensile stress depends on the superposition of incident wave and reflected wave at the bonding interface. Increasing pulse energy and spot diameter intensifies damage at the adhesive interface and reduces the interfacial tensile strength. As CFRP thickness increases, the interlayer tensile stress decreases, and the bonding interface damage is correspondingly reduced. Increasing curvature enlarges the angle between the reflected and incident stress wave at the bonding interface and the back surface, resulting in the reduction of the damage. Applying a metallic constraint to the rear surface of the specimen reduces the magnitude of the reflected tensile stress, thereby mitigating interfacial damage. Conversely, when the rear surface is unconstrained, the reflected tensile stress is higher, resulting in more pronounced interfacial damage.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"198 ","pages":"Article 114876"},"PeriodicalIF":5.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116765","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 : 2026-02-04DOI: 10.1016/j.optlastec.2026.114855
Hongzu Zhang , Li Wang , Bo Li , Hanshuang Li , Guochao Gu , Xu Zhang
This study addresses faint target detection under intense backgrounds by proposing a novel hollow truncated conical external occulter for stray light suppression in imaging systems. Unlike material-dependent transmittance control methods, the design innovatively optimizes transmittance distribution via geometric parameter tuning, significantly reducing edge diffraction and attenuating image-plane stray light. Leveraging TRACEPRO’s optimization capabilities and gradient transmittance diffraction theory, a precise optical model is established, with the occulter’s diffraction and stray light characteristics quantitatively analyzed through numerical optimization workflows. During optimization, the occulter structure and lens configuration are co-optimized to enhance imaging quality while boosting weak-signal detection capability. Combined with an internal occulter and Lyot stop in a multi-stage suppression scheme, the design reduces image-plane background irradiance to the 10−8 order, maintaining effective imaging at a minimum angular separation of 0.5°. This approach discards the traditional method of achieving transmittance variation through multiple materials, but rather leverages flexible geometric structures to control a single material, enabling precise optimization of graded transmittance. It not only exhibits excellent diffraction light suppression performance but also opens up a novel technical pathway for the manufacturing of external occulters. Additionally, it effectively mitigates strong background interference such as solar radiation, significantly enhancing space target detection accuracy and providing reliable support for weak signal acquisition in space target monitoring and exploration missions.
{"title":"Apodized hollow conical occulter with gradient transmittance for stray-light suppression","authors":"Hongzu Zhang , Li Wang , Bo Li , Hanshuang Li , Guochao Gu , Xu Zhang","doi":"10.1016/j.optlastec.2026.114855","DOIUrl":"10.1016/j.optlastec.2026.114855","url":null,"abstract":"<div><div>This study addresses faint target detection under intense backgrounds by proposing a novel hollow truncated conical external occulter for stray light suppression in imaging systems. Unlike material-dependent transmittance control methods, the design innovatively optimizes transmittance distribution via geometric parameter tuning, significantly reducing edge diffraction and attenuating image-plane stray light. Leveraging TRACEPRO’s optimization capabilities and gradient transmittance diffraction theory, a precise optical model is established, with the occulter’s diffraction and stray light characteristics quantitatively analyzed through numerical optimization workflows. During optimization, the occulter structure and lens configuration are co-optimized to enhance imaging quality while boosting weak-signal detection capability. Combined with an internal occulter and Lyot stop in a multi-stage suppression scheme, the design reduces image-plane background irradiance to the 10<sup>−8</sup> order, maintaining effective imaging at a minimum angular separation of 0.5°. This approach discards the traditional method of achieving transmittance variation through multiple materials, but rather leverages flexible geometric structures to control a single material, enabling precise optimization of graded transmittance. It not only exhibits excellent diffraction light suppression performance but also opens up a novel technical pathway for the manufacturing of external occulters. Additionally, it effectively mitigates strong background interference such as solar radiation, significantly enhancing space target detection accuracy and providing reliable support for weak signal acquisition in space target monitoring and exploration missions.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"198 ","pages":"Article 114855"},"PeriodicalIF":5.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116763","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 : 2026-01-31DOI: 10.1016/j.optlastec.2026.114847
Luigi Melchiorre , Giansergio Menduni , Giovanni Magno , Liam O’Faolain , Pietro Patimisco , Vincenzo Spagnolo , Angelo Sampaolo
This paper presents a comparison between quartz-enhanced photoacoustic spectroscopy (QEPAS) and beat-frequency QEPAS (BF-QEPAS) techniques for the sequential detection of methane (C1) and ethane (C2) in the near-infrared spectral range. Both approaches exploit a T-shaped quartz tuning fork (QTF)—coupled with acoustic resonator tubes—as sensitive element but differ fundamentally in the signal generation and acquisition methods. While conventional QEPAS-based approach requires periodic QTF characterization and longer acquisition time, BF-QEPAS enables simultaneous measurement of target gas concentration, QTF resonance frequency and quality factor through analysis of transient response signals. Experiments were performed using a laser diode emitting at a central wavelength of 1683.53 nm, targeting C1 and C2 absorption features. Our results demonstrate that the BF-QEPAS approach significantly reduces measurement time from minutes to few seconds and maintains comparable detection sensitivity, also for broadband absorbers such as ethane. For methane, minimum detection limits (MDLs) of 1.7 parts-per-million (ppm) and 5 ppm were achieved with QEPAS and BF-QEPAS techniques, respectively, while for ethane MDLs of 20 ppm and 62 ppm were obtained, respectively. The BF-QEPAS technique enables continuous, uninterrupted monitoring of both target gases in sequential detection mode, with the simultaneous validation of the measurement through the evaluation of the QTF resonance parameters.
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