Pub Date : 2026-01-01DOI: 10.1016/j.infrared.2025.106349
Xiaopeng Han , Junbo Niu , Xueheng Yan , Yundong Zhang , Fan Wang , Siyu Lin , Wuliji Hasi , Yuan Wei
Fiber curvature sensing has attracted increasing interest due to its high sensitivity, structural versatility, and real-time response. In this work, we propose an intelligent vector curvature sensing system based on a composite optical fiber structure that combines a multimode–OHTC Mach–Zehnder interferometer (MZI) with an etched triple-core fiber Bragg grating (TCF-FBG). Theoretical and experimental analyses verify that the hybrid MZI–TCF-FBG configuration enables high-sensitivity intensity-modulated vector curvature sensing, achieving a maximum sensitivity of 23.41 dB/m−1. To further enhance sensing speed and avoid reliance on wavelength tracking, a spectral pattern–recognition framework is developed using a hybrid convolutional neural network (CNN) and multilayer perceptron (MLP). With unified data preprocessing and cross-validation, the optimized 2D CNN + MLP model yields a minimum mean-square error of 0.002 m−1 and an R2 value approaching 1, demonstrating excellent accuracy and generalization. The proposed method offers a promising route toward rapid, robust, and high-precision vector curvature sensing.
{"title":"Hybrid convolutional neural network optical fiber vector curvature sensing via spectral pattern recognition","authors":"Xiaopeng Han , Junbo Niu , Xueheng Yan , Yundong Zhang , Fan Wang , Siyu Lin , Wuliji Hasi , Yuan Wei","doi":"10.1016/j.infrared.2025.106349","DOIUrl":"10.1016/j.infrared.2025.106349","url":null,"abstract":"<div><div>Fiber curvature sensing has attracted increasing interest due to its high sensitivity, structural versatility, and real-time response. In this work, we propose an intelligent vector curvature sensing system based on a composite optical fiber structure that combines a multimode–OHTC Mach–Zehnder interferometer (MZI) with an etched triple-core fiber Bragg grating (TCF-FBG). Theoretical and experimental analyses verify that the hybrid MZI–TCF-FBG configuration enables high-sensitivity intensity-modulated vector curvature sensing, achieving a maximum sensitivity of 23.41 dB/m<sup>−1</sup>. To further enhance sensing speed and avoid reliance on wavelength tracking, a spectral pattern–recognition framework is developed using a hybrid convolutional neural network (CNN) and multilayer perceptron (MLP). With unified data preprocessing and cross-validation, the optimized 2D CNN + MLP model yields a minimum mean-square error of 0.002 m<sup>−1</sup> and an R<sup>2</sup> value approaching 1, demonstrating excellent accuracy and generalization. The proposed method offers a promising route toward rapid, robust, and high-precision vector curvature sensing.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106349"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01DOI: 10.1016/j.infrared.2025.106345
Sibei Li, Xin Song, Yuxuan Li
The process of detecting small targets in single-frame infrared images poses a considerable challenge, particularly in complex scenes where the appearance of the target is comparable to that of the background. The challenges associated with deep learning methods can be attributed to the feature information loss during the continuous extraction and transmission of features, as well as the inadequate semantic feature correlation between small targets and the background. The proposed BSTNA-Net is an attention-based nested network with a bottleneck Swin Transformer. Specifically, a residual-attention structure incorporating serial channel and spatial attention is combined with a nested U-Net architecture, thereby achieving adaptive feature enhancement while enabling dense feature reuse across skip connections of varying spans. Moreover, a Wavelet Down-sampling Block is employed to supersede traditional pooling layers. This is achieved by integrating wavelet transformation with grouped feature reconstruction, thereby minimizing the loss of information from the deep layers. In addition, the Bottleneck Swin Transformer Block is integrated into the network to process deep feature maps, and the shifted window self-attention mechanism is employed to enhance the global feature extraction capability of the deep neural network, thereby improving the detection and segmentation accuracy of small infrared targets. A series of experiments on the IRSTD-1k and NUDT-SIRST datasets have been conducted, the results of which indicate that the proposed BSTNA-Net is at the leading edge in terms of detection performance and computational efficiency.
{"title":"BSTNA-Net: Nested attention network with bottleneck Swin Transformer for infrared small target detection","authors":"Sibei Li, Xin Song, Yuxuan Li","doi":"10.1016/j.infrared.2025.106345","DOIUrl":"10.1016/j.infrared.2025.106345","url":null,"abstract":"<div><div>The process of detecting small targets in single-frame infrared images poses a considerable challenge, particularly in complex scenes where the appearance of the target is comparable to that of the background. The challenges associated with deep learning methods can be attributed to the feature information loss during the continuous extraction and transmission of features, as well as the inadequate semantic feature correlation between small targets and the background. The proposed BSTNA-Net is an attention-based nested network with a bottleneck Swin Transformer. Specifically, a residual-attention structure incorporating serial channel and spatial attention is combined with a nested U-Net architecture, thereby achieving adaptive feature enhancement while enabling dense feature reuse across skip connections of varying spans. Moreover, a Wavelet Down-sampling Block is employed to supersede traditional pooling layers. This is achieved by integrating wavelet transformation with grouped feature reconstruction, thereby minimizing the loss of information from the deep layers. In addition, the Bottleneck Swin Transformer Block is integrated into the network to process deep feature maps, and the shifted window self-attention mechanism is employed to enhance the global feature extraction capability of the deep neural network, thereby improving the detection and segmentation accuracy of small infrared targets. A series of experiments on the IRSTD-1k and NUDT-SIRST datasets have been conducted, the results of which indicate that the proposed BSTNA-Net is at the leading edge in terms of detection performance and computational efficiency.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106345"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01DOI: 10.1016/j.infrared.2025.106364
Jin Yang , Xiutao Yang , Jun Gou , Hang Yu , Zexu Wang , Yuchao Wei , Laijiang Wei , Chunyu Li , He Yu , Hongxi Zhou , Yun Zhou , Jun Wang
Research on photoconductive devices based on SeTe alloy remains limited, especially in compositional optimization, interface engineering, and scalable manufacturing techniques. Here, we present a Se0.3Te0.7 photoconductive detector optimized for 1550 nm wavelength through pre-metal annealing-enabled TeOx passivation. Annealing the Se0.3Te0.7 alloy prior to electrode deposition forms a TeOx interfacial layer that passivates surface states and reduces dark current by nearly an order of magnitude. The optimized device achieves an enhanced responsivity of 57.7 mA W−1 at −1 V bias with a 10 μm channel length, representing a 58.6 % improvement compared to traditional methods. Device performance is further tunable via channel length and bias voltage, with shorter channels demonstrating superior speed. This work presents a scalable, low-cost fabrication strategy for SeTe-based photodetectors, bridging the gap between material innovation and practical C-band applications in short-wave infrared (SWIR) detection.
基于SeTe合金的光导器件的研究仍然有限，特别是在成分优化，界面工程和可扩展的制造技术方面。在这里，我们提出了一个Se0.3Te0.7光导探测器，通过金属前退火使TeOx钝化，优化为1550 nm波长。在电极沉积之前，对Se0.3Te0.7合金进行退火，形成TeOx界面层，钝化表面状态并将暗电流降低近一个数量级。优化后的器件在- 1 V偏置和10 μm通道长度下的响应度提高到57.7 mA W−1，比传统方法提高了58.6%。器件性能通过通道长度和偏置电压进一步可调，更短的通道显示出更高的速度。这项工作提出了一种可扩展的、低成本的基于set的光电探测器制造策略，弥合了材料创新与短波红外（SWIR）探测中实际c波段应用之间的差距。
{"title":"TeOx interfacial passivation for Se0.3Te0.7 photoconductive detectors at 1550 nm","authors":"Jin Yang , Xiutao Yang , Jun Gou , Hang Yu , Zexu Wang , Yuchao Wei , Laijiang Wei , Chunyu Li , He Yu , Hongxi Zhou , Yun Zhou , Jun Wang","doi":"10.1016/j.infrared.2025.106364","DOIUrl":"10.1016/j.infrared.2025.106364","url":null,"abstract":"<div><div>Research on photoconductive devices based on SeTe alloy remains limited, especially in compositional optimization, interface engineering, and scalable manufacturing techniques. Here, we present a Se<sub>0.3</sub>Te<sub>0.7</sub> photoconductive detector optimized for 1550 nm wavelength through pre-metal annealing-enabled TeO<sub>x</sub> passivation. Annealing the Se<sub>0.3</sub>Te<sub>0.7</sub> alloy prior to electrode deposition forms a TeO<sub>x</sub> interfacial layer that passivates surface states and reduces dark current by nearly an order of magnitude. The optimized device achieves an enhanced responsivity of 57.7 mA W<sup>−1</sup> at −1 V bias with a 10 μm channel length, representing a 58.6 % improvement compared to traditional methods. Device performance is further tunable via channel length and bias voltage, with shorter channels demonstrating superior speed. This work presents a scalable, low-cost fabrication strategy for SeTe-based photodetectors, bridging the gap between material innovation and practical C-band applications in short-wave infrared (SWIR) detection.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"154 ","pages":"Article 106364"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01DOI: 10.1016/j.infrared.2025.106356
Guoqing Wang , Guolin Wang , Jia Yu , Zuozheng Chen , Jinglai Zheng , Buyue Zhao , Shanggeng Li , Liping Liu , Haiming Huang
The high-temperature spectral emissivity of thermal protection materials is critical for the design and evaluation of thermal protection systems. In order to achieve effective traceability of spectral characteristic parameters under hypersonic flight conditions, a system for in-situ measurement of ultra-high temperature spectral emissivity in a high-frequency plasma wind tunnel was developed. The spectral characteristics of material thermal radiation in the plasma wind tunnel were measured using FTIR. The established system can achieve in-situ spectral radiation measurements within a wide temperature range of 1000–2900℃ and a wavelength range of 1.1–7.2 μm. By developing our own pre-stage concentrating system, the response linearity of the measurement system is improved to less than 2 %. The source size effect of the measured sample is less than 1 %. The in situ spectral emissivity of high purity graphite was measured based on the technique. The feasibility of this method was demonstrated by comparing the measured spectral emissivity with the measurement results of the plasma heater. The overall uncertainty of the in-situ emissivity measurement is less than 2.04 % and the relative uncertainty is less than 2.47 % at 2138 K. This technology provides a new method for in-situ acquisition of the surface spectral radiation characteristics of thermal protection materials during dynamic ablation in extremely high-temperature environments.
{"title":"In situ measurement system for ultra-high temperature spectral emissivity of samples under plasma wind tunnel","authors":"Guoqing Wang , Guolin Wang , Jia Yu , Zuozheng Chen , Jinglai Zheng , Buyue Zhao , Shanggeng Li , Liping Liu , Haiming Huang","doi":"10.1016/j.infrared.2025.106356","DOIUrl":"10.1016/j.infrared.2025.106356","url":null,"abstract":"<div><div>The high-temperature spectral emissivity of thermal protection materials is critical for the design and evaluation of thermal protection systems. In order to achieve effective traceability of spectral characteristic parameters under hypersonic flight conditions, a system for in-situ measurement of ultra-high temperature spectral emissivity in a high-frequency plasma wind tunnel was developed. The spectral characteristics of material thermal radiation in the plasma wind tunnel were measured using FTIR. The established system can achieve in-situ spectral radiation measurements within a wide temperature range of 1000–2900℃ and a wavelength range of 1.1–7.2 μm. By developing our own pre-stage concentrating system, the response linearity of the measurement system is improved to less than 2 %. The source size effect of the measured sample is less than 1 %. The in situ spectral emissivity of high purity graphite was measured based on the technique. The feasibility of this method was demonstrated by comparing the measured spectral emissivity with the measurement results of the plasma heater. The overall uncertainty of the in-situ emissivity measurement is less than 2.04 % and the relative uncertainty is less than 2.47 % at 2138 K. This technology provides a new method for in-situ acquisition of the surface spectral radiation characteristics of thermal protection materials during dynamic ablation in extremely high-temperature environments.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106356"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01DOI: 10.1016/j.infrared.2025.106351
Weifeng Zhong , Zhiqiang Long , Yiheng Yang , Xiang Wang , Amei Du , Wen Yang , Changhe Sun , Ruijun Lan , Yingjie Shen
In this paper, a HfSe2/CsPbBr3 heterostructure was prepared and used as a saturable absorber (SA) to modulate a Tm:YAP laser. Under continuous-wave operation, the Tm:YAP crystal was pumped with a diode laser at an absorbed pump power of 12.9 W, producing an output power of 2.35 W at 1995.9 nm and a slope efficiency of 23.2 %. In passively Q-switched mode, the HfSe2/CsPbBr3 heterostructure SA modulated the Tm:YAP laser, resulting in an average output power of 2.1 W and a pulse width of 687.2 ns at 1987.5 nm, with a pulse repetition rate of 112.82 kHz. These parameters correspond to a slope efficiency of 19.8 %, a single-pulse energy of 18.6 µJ, and a peak power of 27.1 W.
{"title":"Diode-pumped passively Q-switched Tm:YAP laser using a HfSe2/CsPbBr3 heterostructure as the saturable absorber","authors":"Weifeng Zhong , Zhiqiang Long , Yiheng Yang , Xiang Wang , Amei Du , Wen Yang , Changhe Sun , Ruijun Lan , Yingjie Shen","doi":"10.1016/j.infrared.2025.106351","DOIUrl":"10.1016/j.infrared.2025.106351","url":null,"abstract":"<div><div>In this paper, a HfSe<sub>2</sub>/CsPbBr<sub>3</sub> heterostructure was prepared and used as a saturable absorber (SA) to modulate a Tm:YAP laser. Under continuous-wave operation, the Tm:YAP crystal was pumped with a diode laser at an absorbed pump power of 12.9 W, producing an output power of 2.35 W at 1995.9 nm and a slope efficiency of 23.2 %. In passively Q-switched mode, the HfSe<sub>2</sub>/CsPbBr<sub>3</sub> heterostructure SA modulated the Tm:YAP laser, resulting in an average output power of 2.1 W and a pulse width of 687.2 ns at 1987.5 nm, with a pulse repetition rate of 112.82 kHz. These parameters correspond to a slope efficiency of 19.8 %, a single-pulse energy of 18.6 µJ, and a peak power of 27.1 W.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106351"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01DOI: 10.1016/j.infrared.2025.106336
Tianjiao Wu , Tianshu Wang , Gang Deng , Baoqun Li , Bowen Chen , Deqi Li , Silun Du , Sunde Wang , Hanyu He , Dongmei Liu , Yan Chen
In this paper, a feasible scheme for low-threshold, switchable multi-wavelength erbium-doped fiber laser is presented. This scheme combines a whispering gallery mode microsphere resonator with fiber taper acting as miniature comb filter within an erbium-doped all-fiber laser system. By exploiting the high Q and nonlinear comb filtering characteristic of the microsphere resonator with the system polarization regulation mechanism, it effectively suppresses the mode competition caused by uniform gain broadening, achieving stable output and flexible switching of low-threshold multi-wavelength lasers without other wavelength stabilization mechanism. According to the experimental results, single-, dual-, triple-, quad-, and quint-wavelength switchable lasers have been successfully achieved, with the lowest laser generation threshold of 3.156 mW. During a 50 min stability test, the maximum wavelength drift is less than 0.008 nm, and the power fluctuation is less than 2.98 dB. This scheme demonstrates significant advantages in terms of compact structure, low pump power requirements, and flexibility in wavelength switchable, providing a new practicable approach for the low-cost integration of multi-wavelength lasers with broad application potential.
{"title":"Ultra-Low threshold switchable multi-wavelength fiber laser via a miniature whispering-gallery-mode comb filter","authors":"Tianjiao Wu , Tianshu Wang , Gang Deng , Baoqun Li , Bowen Chen , Deqi Li , Silun Du , Sunde Wang , Hanyu He , Dongmei Liu , Yan Chen","doi":"10.1016/j.infrared.2025.106336","DOIUrl":"10.1016/j.infrared.2025.106336","url":null,"abstract":"<div><div>In this paper, a feasible scheme for low-threshold, switchable multi-wavelength erbium-doped fiber laser is presented. This scheme combines a whispering gallery mode microsphere resonator with fiber taper acting as miniature comb filter within an erbium-doped all-fiber laser system. By exploiting the high <em>Q</em> and nonlinear comb filtering characteristic of the microsphere resonator with the system polarization regulation mechanism, it effectively suppresses the mode competition caused by uniform gain broadening, achieving stable output and flexible switching of low-threshold multi-wavelength lasers without other wavelength stabilization mechanism. According to the experimental results, single-, dual-, triple-, quad-, and quint-wavelength switchable lasers have been successfully achieved, with the lowest laser generation threshold of 3.156 mW. During a 50 min stability test, the maximum wavelength drift is less than 0.008 nm, and the power fluctuation is less than 2.98 dB. This scheme demonstrates significant advantages in terms of compact structure, low pump power requirements, and flexibility in wavelength switchable, providing a new practicable approach for the low-cost integration of multi-wavelength lasers with broad application potential.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106336"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01DOI: 10.1016/j.infrared.2025.106358
Biao Wu , Hongyi Bai , Laijun Sun , Yanru Fang , Zibo Han , Shihao Zhang
Accurate identification of soybean seed varieties is essential for optimized utilization, as different varieties vary in protein and fat content. This study proposes an ensemble wavelength selection method combined with visible/near-infrared spectroscopy (Vis/NIRS) to identify nine soybean seed varieties. The method works by integrating Partial Least Squares Discriminant Analysis (PLSDA), Random Forest (RF) and Least Absolute Shrinkage and Selection Operator (LASSO) feature importance ranking. Feature scores are normalized and summed to generate an integrated importance score, and a threshold-based strategy is applied to select the most informative wavelengths. This approach takes advantage of different methods and enhances the overall effectiveness of feature selection. These selected wavelengths are then used as inputs to a 1D convolutional neural network (1D-CNN) for variety classification. The proposed method reduced the spectral dimensionality from 1794 to 188 and achieved a classification accuracy of 0.985 on the test set. This study indicates that the combination of visible/near-infrared spectroscopy data and ensemble wavelength selection method provides a new approach for identification of soybean seed varieties.
{"title":"Varieties identification of soybean seed using visible/near-infrared spectroscopy based on ensemble wavelength selection method","authors":"Biao Wu , Hongyi Bai , Laijun Sun , Yanru Fang , Zibo Han , Shihao Zhang","doi":"10.1016/j.infrared.2025.106358","DOIUrl":"10.1016/j.infrared.2025.106358","url":null,"abstract":"<div><div>Accurate identification of soybean seed varieties is essential for optimized utilization, as different varieties vary in protein and fat content. This study proposes an ensemble wavelength selection method combined with visible/near-infrared spectroscopy (Vis/NIRS) to identify nine soybean seed varieties. The method works by integrating Partial Least Squares Discriminant Analysis (PLSDA), Random Forest (RF) and Least Absolute Shrinkage and Selection Operator (LASSO) feature importance ranking. Feature scores are normalized and summed to generate an integrated importance score, and a threshold-based strategy is applied to select the most informative wavelengths. This approach takes advantage of different methods and enhances the overall effectiveness of feature selection. These selected wavelengths are then used as inputs to a 1D convolutional neural network (1D-CNN) for variety classification. The proposed method reduced the spectral dimensionality from 1794 to 188 and achieved a classification accuracy of 0.985 on the test set. This study indicates that the combination of visible/near-infrared spectroscopy data and ensemble wavelength selection method provides a new approach for identification of soybean seed varieties.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106358"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-29DOI: 10.1016/j.infrared.2025.106360
Wenfang Lin , Conghui Huang , Shulong Zhang , Min Xu , Siliang Tao , Shanming Li , Chengchun Zhao , Qiannan Fang , Xisheng Ye , Yin Hang
The self-Q-switching (SQS) laser performance on Nd-doped crystal at 1.3 μm has been reported for the first time, as far as is known. On Sr0.7Nd0.05La0.25Mg0.3Al11.7O19 (Nd:ASL) disorder crystal, a SQS dual-wavelength laser at 1339.9 and 1370.3 nm with output power up to 1.65 W was obtained under an absorbed pump power of 10.13 W with slope and optical-to-optical efficiencies of 22.3 % and 16.3 %, respectively. Furthermore, an on-surface optical axis quartz birefringent filter (BRF) was inserted in the V-folded cavity to tune the laser wavelength. Lasers at 1306.4, and approximately 1340, 1370, or 1391 nm were obtained. The experimental results indicated that σ polarization direction Nd:ASL is capable of producing dual-wavelength lasers at 1339.9 and 1370.3 nm, which was potential to be employed as the source of THz radiation. Besides, Nd:ASL crystals are enable to generate tunable lasers near 1370 and 1391 nm.
{"title":"Self-Q-switching laser performance of Nd:ASL crystals at 1.3 μm","authors":"Wenfang Lin , Conghui Huang , Shulong Zhang , Min Xu , Siliang Tao , Shanming Li , Chengchun Zhao , Qiannan Fang , Xisheng Ye , Yin Hang","doi":"10.1016/j.infrared.2025.106360","DOIUrl":"10.1016/j.infrared.2025.106360","url":null,"abstract":"<div><div>The self-Q-switching (SQS) laser performance on Nd-doped crystal at 1.3 μm has been reported for the first time, as far as is known. On Sr<sub>0.7</sub>Nd<sub>0.05</sub>La<sub>0.25</sub>Mg<sub>0.3</sub>Al<sub>11.7</sub>O<sub>19</sub> (Nd:ASL) disorder crystal, a SQS dual-wavelength laser at 1339.9 and 1370.3 nm with output power up to 1.65 W was obtained under an absorbed pump power of 10.13 W with slope and optical-to-optical efficiencies of 22.3 % and 16.3 %, respectively. Furthermore, an on-surface optical axis quartz birefringent filter (BRF) was inserted in the V-folded cavity to tune the laser wavelength. Lasers at 1306.4, and approximately 1340, 1370, or 1391 nm were obtained. The experimental results indicated that σ polarization direction Nd:ASL is capable of producing dual-wavelength lasers at 1339.9 and 1370.3 nm, which was potential to be employed as the source of THz radiation. Besides, Nd:ASL crystals are enable to generate tunable lasers near 1370 and 1391 nm.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"154 ","pages":"Article 106360"},"PeriodicalIF":3.4,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-26DOI: 10.1016/j.infrared.2025.106353
Tianlei Ma , Liang Fu , Jinzhu Peng , Fang-Lue Zhang , Heng Zhang , Xiangbo Feng , Teng Wang , Lu Xin
Recent advancements in deep learning-based detection methods have led to substantial improvements in the performance of infrared small target detection (IRSTD). However, most methods rely solely on the original image and overlook the valuable prior knowledge it contains. As a result, these methods exhibit limited capability in extracting and enhancing target features. To tackle this problem, a fusion framework named the Infrared Small Target Detection Fusion Network (ISTDFN) has been developed, consisting mainly of a decomposition network and a detection network. Initially, to guide the network’s focus toward target features, we use the decomposition network to factorize images into sparse and low-rank components. The target information will primarily be contained in the sparse components. Furthermore, to improve the efficiency of feature extraction, the detection network incorporates a feature amplifier based on the Rayleigh distribution, which is inspired by the thermal diffusion model of small targets in physics, enabling dynamic enhancement of target features. Finally, after extracting and enhancing features from the two decomposed components, a singular value feature fusion (SVFF) module is applied in the detection network to facilitate effective information interaction and fusion. Comprehensive experiments demonstrate that the proposed approach can accurately and efficiently detect targets, even under challenging background conditions.
{"title":"Infrared Small Target Detection Fusion Network based on singular value decomposition and Rayleigh feature amplifier","authors":"Tianlei Ma , Liang Fu , Jinzhu Peng , Fang-Lue Zhang , Heng Zhang , Xiangbo Feng , Teng Wang , Lu Xin","doi":"10.1016/j.infrared.2025.106353","DOIUrl":"10.1016/j.infrared.2025.106353","url":null,"abstract":"<div><div>Recent advancements in deep learning-based detection methods have led to substantial improvements in the performance of infrared small target detection (IRSTD). However, most methods rely solely on the original image and overlook the valuable prior knowledge it contains. As a result, these methods exhibit limited capability in extracting and enhancing target features. To tackle this problem, a fusion framework named the Infrared Small Target Detection Fusion Network (ISTDFN) has been developed, consisting mainly of a decomposition network and a detection network. Initially, to guide the network’s focus toward target features, we use the decomposition network to factorize images into sparse and low-rank components. The target information will primarily be contained in the sparse components. Furthermore, to improve the efficiency of feature extraction, the detection network incorporates a feature amplifier based on the Rayleigh distribution, which is inspired by the thermal diffusion model of small targets in physics, enabling dynamic enhancement of target features. Finally, after extracting and enhancing features from the two decomposed components, a singular value feature fusion (SVFF) module is applied in the detection network to facilitate effective information interaction and fusion. Comprehensive experiments demonstrate that the proposed approach can accurately and efficiently detect targets, even under challenging background conditions.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106353"},"PeriodicalIF":3.4,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-26DOI: 10.1016/j.infrared.2025.106332
Lei Yu , Qing Yan , Yafei Hou , Huijie Wang , Xulei Yang , Wenjun He , Yajun You , Yi Liu , Xiujian Chou
A novel technique for microwave frequency measurement (MFM) based on Brillouin fiber laser with a compression ratio exceeding four orders of magnitude is proposed. This method exploits the difference in the propagation velocities of light and sound within a Brillouin resonator, resulting in a spectral compression ratio of 1.82 × 104 between the Brillouin frequency shift and the input optical wavelength. In contrast to existing MFM, this design not only exhibits a wide measurement range but also offers high frequency resolution. In the experiment, the unknown microwave signal in the pump path is first modulated into a single-sideband format using an optical filter and an intensity modulator. The modulated signal acts as the pump to stimulate Brillouin scattering, and the linewidth of the generated Brillouin laser is significantly narrowed through a cascaded resonant cavity comprising two single-mode fiber segments of 500 m and 50 m, respectively. By detecting the beat frequency of the Brillouin lasers in the probe path, wideband MFM is achieved. A 45 GHz broadband microwave spectrum is successfully compressed into a 2.5 MHz frequency domain window at low frequency, achieved by applying a fixed microwave frequency offset based on spectral compression. The frequency resolution was improved to 8.8 MHz using Brillouin laser. Repeated measurements confirmed that the maximum measurement error of the system is 5 MHz. This design provides a feasible solution for a low-cost MFM with optimal performance.
{"title":"Four orders spectral compression of Brillouin fiber laser for broadband microwave frequency measurement","authors":"Lei Yu , Qing Yan , Yafei Hou , Huijie Wang , Xulei Yang , Wenjun He , Yajun You , Yi Liu , Xiujian Chou","doi":"10.1016/j.infrared.2025.106332","DOIUrl":"10.1016/j.infrared.2025.106332","url":null,"abstract":"<div><div>A novel technique for microwave frequency measurement (MFM) based on Brillouin fiber laser with a compression ratio exceeding four orders of magnitude is proposed. This method exploits the difference in the propagation velocities of light and sound within a Brillouin resonator, resulting in a spectral compression ratio of 1.82 × 10<sup>4</sup> between the Brillouin frequency shift and the input optical wavelength. In contrast to existing MFM, this design not only exhibits a wide measurement range but also offers high frequency resolution. In the experiment, the unknown microwave signal in the pump path is first modulated into a single-sideband format using an optical filter and an intensity modulator. The modulated signal acts as the pump to stimulate Brillouin scattering, and the linewidth of the generated Brillouin laser is significantly narrowed through a cascaded resonant cavity comprising two single-mode fiber segments of 500 m and 50 m, respectively. By detecting the beat frequency of the Brillouin lasers in the probe path, wideband MFM is achieved. A 45 GHz broadband microwave spectrum is successfully compressed into a 2.5 MHz frequency domain window at low frequency, achieved by applying a fixed microwave frequency offset based on spectral compression. The frequency resolution was improved to 8.8 MHz using Brillouin laser. Repeated measurements confirmed that the maximum measurement error of the system is 5 MHz. This design provides a feasible solution for a low-cost MFM with optimal performance.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106332"},"PeriodicalIF":3.4,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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