Pub Date : 2026-01-01DOI: 10.1016/j.infrared.2025.106343
Yongxiang Zhang, Jiancheng Zhao, Ziyi An, Lijiao Zu, Shi Qiu, Wa Jin, Xinghu Fu
A helical twisted four-core fiber (FCF) sensor with a center-offset is proposed and fabricated. The sensor structure is composed of a single-mode fiber (SMF)-FCF-SMF configuration. A periodic helical structure with a center-offset was fabricated in the FCF region. The presence of this center-offset helical structure introduces birefringence into the FCF, thereby forming an interferometer. Experimental investigations on the sensor’s performance in torsion and strain sensing were conducted. The results show that within the torsional rotation range of −20.94 rad/m to 20.94 rad/m, the sensor achieves a maximum torsion sensitivity of −118 pm/(rad/m). The helical structure enables the recognition of torsion direction. Within the strain range of 0 to 1300 μɛ, the sensor exhibits a maximum strain sensitivity of −4.95 nm/mɛ. The center-offset effectively enhances the sensor’s strain sensitivity. These findings demonstrate that the sensor possesses high sensitivity to both torsion and strain. The center-offset helical structure significantly improves torsion and strain sensitivity, allows identification of torsion magnitude and direction, and effectively detects strain.
{"title":"A torsion and strain sensor based on center-offset helical structure of four-core optical fiber","authors":"Yongxiang Zhang, Jiancheng Zhao, Ziyi An, Lijiao Zu, Shi Qiu, Wa Jin, Xinghu Fu","doi":"10.1016/j.infrared.2025.106343","DOIUrl":"10.1016/j.infrared.2025.106343","url":null,"abstract":"<div><div>A helical twisted four-core fiber (FCF) sensor with a center-offset is proposed and fabricated. The sensor structure is composed of a single-mode fiber (SMF)-FCF-SMF configuration. A periodic helical structure with a center-offset was fabricated in the FCF region. The presence of this center-offset helical structure introduces birefringence into the FCF, thereby forming an interferometer. Experimental investigations on the sensor’s performance in torsion and strain sensing were conducted. The results show that within the torsional rotation range of −20.94 rad/m to 20.94 rad/m, the sensor achieves a maximum torsion sensitivity of −118 pm/(rad/m). The helical structure enables the recognition of torsion direction. Within the strain range of 0 to 1300 μɛ, the sensor exhibits a maximum strain sensitivity of −4.95 nm/mɛ. The center-offset effectively enhances the sensor’s strain sensitivity. These findings demonstrate that the sensor possesses high sensitivity to both torsion and strain. The center-offset helical structure significantly improves torsion and strain sensitivity, allows identification of torsion magnitude and direction, and effectively detects strain.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106343"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880168","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.2025.106348
Fajian He , Lulu Xu , Qianqiao Dong , Xinyi Xu , Xuejun Zhang , Shixun Dai
In this work, the effect of WO3 incorporation on mid-infrared luminescence is systematically studied for the first time in heavily Er3+-doped TeO2-ZnO-La2O3-WO3 glasses. Results show that WO3 content strongly influences the emission behavior from visible to mid-infrared regions, with related energy transfer mechanisms clarified. The introduction of WO3 effectively suppresses the up-conversion emission of Er3+, thereby promoting the down-conversion transition (Er3+: 4I11/2 → 4I13/2) and significantly enhancing both the intensity and bandwidth of mid-infrared emission. An equivalent three-level Stark splitting model is proposed to explain the WO3-induced spectral broadening. The optimized 66TeO2-20ZnO-8La2O3-4WO3-2Er2O3 (mol%) glass exhibits high thermal stability (ΔT = 143 °C), a large 2.7 µm emission cross-section (0.82 × 10-20 cm2), and a broad effective bandwidth (145 nm), making it highly suitable for broadband mid-infrared devices. Fiber drawn from this composition show strong 2.7 µm emission under 980 nm pumping, confirming its potential as a gain medium for mid-infrared fiber lasers.
{"title":"Broadening and enhancement of mid-infrared emission via WO3 incorporation in Er3+-doped tellurite glasses","authors":"Fajian He , Lulu Xu , Qianqiao Dong , Xinyi Xu , Xuejun Zhang , Shixun Dai","doi":"10.1016/j.infrared.2025.106348","DOIUrl":"10.1016/j.infrared.2025.106348","url":null,"abstract":"<div><div>In this work, the effect of WO<sub>3</sub> incorporation on mid-infrared luminescence is systematically studied for the first time in heavily Er<sup>3+</sup>-doped TeO<sub>2</sub>-ZnO-La<sub>2</sub>O<sub>3</sub>-WO<sub>3</sub> glasses. Results show that WO<sub>3</sub> content strongly influences the emission behavior from visible to mid-infrared regions, with related energy transfer mechanisms clarified. The introduction of WO<sub>3</sub> effectively suppresses the up-conversion emission of Er<sup>3+</sup>, thereby promoting the down-conversion transition (Er<sup>3+</sup>: <sup>4</sup>I<sub>11/2</sub> → <sup>4</sup>I<sub>13/2</sub>) and significantly enhancing both the intensity and bandwidth of mid-infrared emission. An equivalent three-level Stark splitting model is proposed to explain the WO<sub>3</sub>-induced spectral broadening. The optimized 66TeO<sub>2</sub>-20ZnO-8La<sub>2</sub>O<sub>3</sub>-4WO<sub>3</sub>-2Er<sub>2</sub>O<sub>3</sub> (mol%) glass exhibits high thermal stability (ΔT = 143 °C), a large 2.7 µm emission cross-section (0.82 × 10<sup>-20</sup> cm<sup>2</sup>), and a broad effective bandwidth (145 nm), making it highly suitable for broadband mid-infrared devices. Fiber drawn from this composition show strong 2.7 µm emission under 980 nm pumping, confirming its potential as a gain medium for mid-infrared fiber lasers.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106348"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880169","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.2025.106361
Tingting Yao, Yu Zhang, Meiwen Zhu, Qing Hu
Infrared small target detection plays a crucial role in military and security applications. However, the complex background noise and blurred boundary of the target degrade the detection performance of existing methods. In this paper, a noise suppression and object enhancement network has been proposed to overcome these issues. First, a noise suppression module (NSM) is designed. The interference of noise is suppressed, and more accurate feature representation of the target is extracted. Furthermore, an edge enhancement module (EEM) has been designed to extract more boundary information of small targets with indistinct contours, thereby improving the localization accuracy of the network. Finally, a multi-scale attention enhanced fusion module (MAEFM) is devised. A joint attention enhancement block (JAEB) is introduced in each layer, and multi-scale features are effectively fused, which further strengthens the feature description ability of the network for small targets. Experimental results on two widely used datasets demonstrate that the proposed network could achieve superior detection accuracy for infrared small targets compared with other state-of-the-art approaches.
{"title":"NSOE-Net: Noise suppression and object enhancement network for infrared small target detection","authors":"Tingting Yao, Yu Zhang, Meiwen Zhu, Qing Hu","doi":"10.1016/j.infrared.2025.106361","DOIUrl":"10.1016/j.infrared.2025.106361","url":null,"abstract":"<div><div>Infrared small target detection plays a crucial role in military and security applications. However, the complex background noise and blurred boundary of the target degrade the detection performance of existing methods. In this paper, a noise suppression and object enhancement network has been proposed to overcome these issues. First, a noise suppression module (NSM) is designed. The interference of noise is suppressed, and more accurate feature representation of the target is extracted. Furthermore, an edge enhancement module (EEM) has been designed to extract more boundary information of small targets with indistinct contours, thereby improving the localization accuracy of the network. Finally, a multi-scale attention enhanced fusion module (MAEFM) is devised. A joint attention enhancement block (JAEB) is introduced in each layer, and multi-scale features are effectively fused, which further strengthens the feature description ability of the network for small targets. Experimental results on two widely used datasets demonstrate that the proposed network could achieve superior detection accuracy for infrared small targets compared with other state-of-the-art approaches.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106361"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880177","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.2025.106354
Liping Zhang, Haitao He, Meiling Zhang, Junyan Su
The efficient detection of Terahertz (THz) waves remains a pivotal yet challenging frontier in scientific research. This study delves into THz wave detection in Field-Effect Transistors (FETs) with quantum effect. By employing a self-consistent quantum hydrodynamic model and boundary conditions, we derived dispersion relation and the detector’s responsivity. Numerical simulations were conducted to explore the impact of quantum effects, electron interactions with phonons and impurities, and electron fluid viscosity on the responsivity of THz waves in FETs. The findings indicate a significant enhancement in responsivity due to quantum effects, whereas electron–phonon/impurity interactions and electron fluid viscosity tend to diminish it. These theoretical findings provide critical insights for experimental optimization and the development of high-performance THz detectors. In summary, this study demonstrates substantial potential for practical applications.
{"title":"Research on THz wave detection in field-effect transistors with quantum effect","authors":"Liping Zhang, Haitao He, Meiling Zhang, Junyan Su","doi":"10.1016/j.infrared.2025.106354","DOIUrl":"10.1016/j.infrared.2025.106354","url":null,"abstract":"<div><div>The efficient detection of Terahertz (THz) waves remains a pivotal yet challenging frontier in scientific research. This study delves into THz wave detection in Field-Effect Transistors (FETs) with quantum effect. By employing a self-consistent quantum hydrodynamic model and boundary conditions, we derived dispersion relation and the detector’s responsivity. Numerical simulations were conducted to explore the impact of quantum effects, electron interactions with phonons and impurities, and electron fluid viscosity on the responsivity of THz waves in FETs. The findings indicate a significant enhancement in responsivity due to quantum effects, whereas electron–phonon/impurity interactions and electron fluid viscosity tend to diminish it. These theoretical findings provide critical insights for experimental optimization and the development of high-performance THz detectors. In summary, this study demonstrates substantial potential for practical applications.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"153 ","pages":"Article 106354"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880247","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.2026.106366
Zeqian Liu , Hui Chen , Jiashuo An , Junhong Chen , Bingzheng Yan , Yulei Wang , Zhiwei Lu , Zhenxu Bai
Laguerre-Gaussian (LG) beams carrying orbital angular momentum (OAM) demonstrate enhanced information-carrying capacity, making them particularly valuable for high-capacity optical communications. Additionally, petal-like LG beams exhibit unique advantages for spin angular velocity measurements due to their distinctive intensity profiles and phase singularity characteristics. However, current laser systems face significant challenges in achieving direct switching between high-order vortex beams and petal-like beams outputs. This study presents a side-pumped Nd:YAG laser system capable of direct switching between high-order vortex beams and petal-like beams. By introducing specifically engineered spot defects of varying dimensions in the resonator mirrors of a side-pumped Nd:YAG laser system, we demonstrate tunable vortex beam generation from 1st to 6th order through cavity length adjustments. Furthermore, mode conversion between vortex and petal-like beams is achieved using an off-axis pumping scheme, in which the pump beam is intentionally displaced from the center of the defect. Using this approach, stable petal-like LG modes ranging from LG0,1 to LG0,12. are successfully generated. To the best of our knowledge, this work demonstrates for the first time an intracavity LG mode conversion strategy that combines engineered spot defects with off-axis pumping, providing a compact and versatile platform for flexible structured-light generation.
{"title":"Intracavity switchable Laguerre–Gaussian mode generation in a side-pumped Nd:YAG laser via spot defect and off-axis pumping","authors":"Zeqian Liu , Hui Chen , Jiashuo An , Junhong Chen , Bingzheng Yan , Yulei Wang , Zhiwei Lu , Zhenxu Bai","doi":"10.1016/j.infrared.2026.106366","DOIUrl":"10.1016/j.infrared.2026.106366","url":null,"abstract":"<div><div>Laguerre-Gaussian (LG) beams carrying orbital angular momentum (OAM) demonstrate enhanced information-carrying capacity, making them particularly valuable for high-capacity optical communications. Additionally, petal-like LG beams exhibit unique advantages for spin angular velocity measurements due to their distinctive intensity profiles and phase singularity characteristics. However, current laser systems face significant challenges in achieving direct switching between high-order vortex beams and petal-like beams outputs. This study presents a side-pumped Nd:YAG<!--> <!-->laser system capable of direct switching between high-order vortex beams and petal-like beams. By introducing specifically engineered spot defects of varying dimensions in the resonator mirrors of a side-pumped Nd:YAG<!--> <!-->laser system, we demonstrate tunable vortex beam generation from 1st to 6th order through cavity length adjustments. Furthermore, mode conversion between vortex and petal-like beams is achieved using an off-axis pumping scheme, in which the pump beam is intentionally displaced from the center of the defect. Using this approach, stable petal-like LG modes ranging from LG<sub>0,1</sub> to LG<sub>0,12</sub>. are successfully generated. To the best of our knowledge, this work demonstrates for the first time an intracavity LG mode conversion strategy that combines engineered spot defects with off-axis pumping, providing a compact and versatile platform for flexible structured-light generation.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"154 ","pages":"Article 106366"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923919","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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