Pub Date : 2026-05-01Epub Date: 2026-02-13DOI: 10.1016/j.infrared.2026.106476
Yue Zhao , Yueji Wang , Ruyu Shi , Shuhan Bao , Zijian Wang , Yongji Yu , Guangyong Jin
This paper reports a mid-infrared (MIR) optical parametric oscillator (OPO) pumped by a Ytterbium-doped (Yb-doped) fiber laser, utilizing a dual-crystal configuration with multi-grating MgO:PPLN crystals. Simultaneous output of narrow-linewidth dual-wavelength lasers was achieved across a broadband tuning range. By jointly controlling the grating periods and operating temperatures of the two crystals, continuous tuning and simultaneous extraction of dual-wavelength mid-infrared radiation were successfully realized. Furthermore, the spectral linewidths were effectively narrowed. Furthermore, a Fabry-Perot (F-P) etalon was introduced into the system; by fine-tuning its inclination angle, the spectral linewidths of the dual-wavelength output were simultaneously narrowed. The experimental results demonstrate that by pumping the OPO with a 1064 nm fiber laser, continuous tuning and synchronized dual-wavelength generation were achieved within the broad spectral range of 2.70–4.20 μm. After linewidth narrowing via the F-P etalon, the linewidths of the mid-infrared lasers were effectively reduced to approximately 1 nm. Within this tuning range, a maximum total output power of 2.87 W was obtained, with beam quality factors M2 of less than 2 and power stability better than 3.5%.
{"title":"Widely Tunable, Narrow-Linewidth, Dual-Wavelength Mid-Infrared optical parametric oscillator Based on MgO:PPLN crystal","authors":"Yue Zhao , Yueji Wang , Ruyu Shi , Shuhan Bao , Zijian Wang , Yongji Yu , Guangyong Jin","doi":"10.1016/j.infrared.2026.106476","DOIUrl":"10.1016/j.infrared.2026.106476","url":null,"abstract":"<div><div>This paper reports a mid-infrared (MIR) optical parametric oscillator (OPO) pumped by a Ytterbium-doped (Yb-doped) fiber laser, utilizing a dual-crystal configuration with multi-grating MgO:PPLN crystals. Simultaneous output of narrow-linewidth dual-wavelength lasers was achieved across a broadband tuning range. By jointly controlling the grating periods and operating temperatures of the two crystals, continuous tuning and simultaneous extraction of dual-wavelength mid-infrared radiation were successfully realized. Furthermore, the spectral linewidths were effectively narrowed. Furthermore, a Fabry-Perot (F-P) etalon was introduced into the system; by fine-tuning its inclination angle, the spectral linewidths of the dual-wavelength output were simultaneously narrowed. The experimental results demonstrate that by pumping the OPO with a 1064 nm fiber laser, continuous tuning and synchronized dual-wavelength generation were achieved within the broad spectral range of 2.70–4.20 μm. After linewidth narrowing via the F-P etalon, the linewidths of the mid-infrared lasers were effectively reduced to approximately 1 nm. Within this tuning range, a maximum total output power of 2.87 W was obtained, with beam quality factors M<sup>2</sup> of less than 2 and power stability better than 3.5%.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"155 ","pages":"Article 106476"},"PeriodicalIF":3.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386215","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 : 2026-05-01Epub Date: 2026-02-19DOI: 10.1016/j.infrared.2026.106481
Kaihua Zhang , Ziqing Xi , Longtian Xie , Kun Yu , Yufang Liu
Dynamic thermal regulation technology enables efficient thermal management through tunable devices, demonstrating broad prospects in addressing global energy challenges. Such regulators can alter their optical properties in response to external stimuli such as temperature or mechanical actuation, thereby achieving passive or active thermal control. However, achieving flexible and rapid dynamic thermal regulation in high temperature, high humidity environments remains challenging. To address this issue, this study proposes a dynamic thermal regulator based on the In3SbTe2 (IST) phase-change material. It enables flexible and rapid active control through voltage application, making it suitable for adaptive radiative thermal management. Leveraging the phase-change properties of the IST layer, this regulator can adjust thermal emissivity between 0.16 and 0.9 within the atmospheric transparency window. Thermal performance analysis reveals that under high temperature conditions, the regulator’s average surface temperature can be maintained 15.62 K below ambient temperature. Conversely, in low-temperature environments, its cooling effect is suppressed to achieve thermal insulation, with net heat loss restrained to less than 1.54 K below ambient temperature. The voltage-driven mechanism enables faster and more proactive dynamic adjustments in response to changes in the external environment, thereby achieving superior regulation performance. The regulator features a simple structure and utilizes readily available materials, making it suitable for large-scale production and promising broad market application prospects. By combining material innovation, structural optimization, and a more responsive voltage-driven mechanism, the design of this high-performance regulator lays a solid foundation for building more sustainable building energy systems and offers a forward-looking solution for energy efficiency across diverse climatic conditions.
{"title":"Voltage-driven dynamic thermal regulator based on In3SbTe2 phase-change material for adaptive radiative cooling and insulation","authors":"Kaihua Zhang , Ziqing Xi , Longtian Xie , Kun Yu , Yufang Liu","doi":"10.1016/j.infrared.2026.106481","DOIUrl":"10.1016/j.infrared.2026.106481","url":null,"abstract":"<div><div>Dynamic thermal regulation technology enables efficient thermal management through tunable devices, demonstrating broad prospects in addressing global energy challenges. Such regulators can alter their optical properties in response to external stimuli such as temperature or mechanical actuation, thereby achieving passive or active thermal control. However, achieving flexible and rapid dynamic thermal regulation in high temperature, high humidity environments remains challenging. To address this issue, this study proposes a dynamic thermal regulator based on the In<sub>3</sub>SbTe<sub>2</sub> (IST) phase-change material. It enables flexible and rapid active control through voltage application, making it suitable for adaptive radiative thermal management. Leveraging the phase-change properties of the IST layer, this regulator can adjust thermal emissivity between 0.16 and 0.9 within the atmospheric transparency window. Thermal performance analysis reveals that under high temperature conditions, the regulator’s average surface temperature can be maintained 15.62 K below ambient temperature. Conversely, in low-temperature environments, its cooling effect is suppressed to achieve thermal insulation, with net heat loss restrained to less than 1.54 K below ambient temperature. The voltage-driven mechanism enables faster and more proactive dynamic adjustments in response to changes in the external environment, thereby achieving superior regulation performance. The regulator features a simple structure and utilizes readily available materials, making it suitable for large-scale production and promising broad market application prospects. By combining material innovation, structural optimization, and a more responsive voltage-driven mechanism, the design of this high-performance regulator lays a solid foundation for building more sustainable building energy systems and offers a forward-looking solution for energy efficiency across diverse climatic conditions.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"155 ","pages":"Article 106481"},"PeriodicalIF":3.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386217","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}
The turbine disk of an aero-engine is a vital component that endures high temperatures and strong stress loads, making the measurement of its temperature distribution essential. Current methods for measuring the temperature distribution of a turbine disk are not effective for online use due to high rotational speeds, challenging measurement conditions, and limited space. Therefore, this study introduces an optical array-pyrometer for assessing the turbine disk’s temperature distribution. Initially, a 3-hour thermal stability test was conducted on a tiny optical probe at 500°C, showing that the energy transmission efficiency and structural stability of the probe remained steady, and the optical-electric conversion linearity was maintained. Next, an accuracy test using a static alloy sample was performed. The maximum measurement error for colorimetric thermometry was 1.73%, significantly lower than the 13.88% error observed with brightness thermometry. Finally, the optical array-pyrometer was employed to measure a rotating high-temperature disk sample, and the resulting temperature distribution accurately reflected the sample’s true temperature distribution. The optical array-pyrometer uses high-speed single-point temperature measurement, and its array-based design compensates for the slower frame rate of the infrared thermal imager, offering a new method for online measurement of the turbine disk temperature distribution.
{"title":"Optical array-pyrometer for measuring temperature distribution of aero-engine turbine disk","authors":"Zezhan Zhang , Hairui Huang , Zixiang Zhang , Wei Zhang , Jiawen Xu , Shan Gao , Chao Wang , Yi Niu , Jing Jiang","doi":"10.1016/j.infrared.2026.106480","DOIUrl":"10.1016/j.infrared.2026.106480","url":null,"abstract":"<div><div>The turbine disk of an aero-engine is a vital component that endures high temperatures and strong stress loads, making the measurement of its temperature distribution essential. Current methods for measuring the temperature distribution of a turbine disk are not effective for online use due to high rotational speeds, challenging measurement conditions, and limited space. Therefore, this study introduces an optical array-pyrometer for assessing the turbine disk’s temperature distribution. Initially, a 3-hour thermal stability test was conducted on a tiny optical probe at 500°C, showing that the energy transmission efficiency and structural stability of the probe remained steady, and the optical-electric conversion linearity was maintained. Next, an accuracy test using a static alloy sample was performed. The maximum measurement error for colorimetric thermometry was 1.73%, significantly lower than the 13.88% error observed with brightness thermometry. Finally, the optical array-pyrometer was employed to measure a rotating high-temperature disk sample, and the resulting temperature distribution accurately reflected the sample’s true temperature distribution. The optical array-pyrometer uses high-speed single-point temperature measurement, and its array-based design compensates for the slower frame rate of the infrared thermal imager, offering a new method for online measurement of the turbine disk temperature distribution.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"155 ","pages":"Article 106480"},"PeriodicalIF":3.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386230","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 : 2026-05-01Epub Date: 2026-02-05DOI: 10.1016/j.infrared.2026.106449
Saima Kanwal , Hussein H.N. Al Taee , Mir Hamid Rezaei , Norah A.M. Alsaif , Saleh Chebaane
We present a highly efficient optical sensor based on the excitation of Fabry-Perot (FP) in a hybrid dielectric-metal multilayer structure. The proposed configuration, comprising a thin gold film, periodic SiO2/Al2O3 layers, a sensing region, and a ground metal. This configuration supports ultra-narrowband resonances and perfect absorption, enabling precise detection of minor refractive index variations. Using the transfer matrix method (TMM), the sensor exhibits a refractive index sensitivity of 1310 nm/RIU with an exceptionally high figure-of-merit (FOMn) of 2569 RIU−1 and a quality-factor (Q) of 3025, alongside an intensity-based sensitivity of 968 RIU−1 and a corresponding FOMI of 7.06 × 105 RIU−1. The optical response can be tuned by altering the dielectric materials, stacking order, or structural parameters. Numerical results confirm excellent agreement with FP resonance theory, validating the design’s accuracy and robustness. These features establish the proposed sensor as a robust and versatile platform for label-free detection and advanced optical biosensing applications.
{"title":"Ultra-narrowband high-sensitivity multispectral sensor enabled by Fabry-Perot resonances for label-free detection","authors":"Saima Kanwal , Hussein H.N. Al Taee , Mir Hamid Rezaei , Norah A.M. Alsaif , Saleh Chebaane","doi":"10.1016/j.infrared.2026.106449","DOIUrl":"10.1016/j.infrared.2026.106449","url":null,"abstract":"<div><div>We present a highly efficient optical sensor based on the excitation of Fabry-Perot (FP) in a hybrid dielectric-metal multilayer structure. The proposed configuration, comprising a thin gold film, periodic SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> layers, a sensing region, and a ground metal. This configuration supports ultra-narrowband resonances and perfect absorption, enabling precise detection of minor refractive index variations. Using the transfer matrix method (TMM), the sensor exhibits a refractive index sensitivity of 1310 nm/RIU with an exceptionally high figure-of-merit (FOM<em><sub>n</sub></em>) of 2569 RIU<sup>−1</sup> and a quality-factor (<em>Q</em>) of 3025, alongside an intensity-based sensitivity of 968 RIU<sup>−1</sup> and a corresponding FOM<em><sub>I</sub></em> of 7.06 × 10<sup>5</sup> RIU<sup>−1</sup>. The optical response can be tuned by altering the dielectric materials, stacking order, or structural parameters. Numerical results confirm excellent agreement with FP resonance theory, validating the design’s accuracy and robustness. These features establish the proposed sensor as a robust and versatile platform for label-free detection and advanced optical biosensing applications.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"155 ","pages":"Article 106449"},"PeriodicalIF":3.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386273","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 : 2026-05-01Epub Date: 2026-02-13DOI: 10.1016/j.infrared.2026.106475
Huazhong Zhang , Rong Yang , Mian Zhong , Xia Lei , Juhang Yin , Ming Yang , Xiaoguang Tu , Fei Li , Xiaoqing Xing , Chao Zhou
To address the problems of low prediction accuracy and poor stability in traditional BP neural networks applied to quantitative defect depth evaluation of composite materials in civil aircraft, this study proposes an improved defect depth prediction model based on a BP neural network optimized using a Tent chaos enhanced Particle Swarm Optimization algorithm (Tent-PSO-BP). This algorithm integrates the PSO algorithm to effectively determine the optimal initial parameters of the network, thereby enhancing prediction accuracy. Furthermore, the Tent chaotic mapping strategy is employed to initialize the population in the PSO algorithm, ensuring a uniform distribution of initial parameters and mitigating the stability issues commonly encountered in traditional BP neural networks during prediction tasks. Results from ablation experiments demonstrates that the improved Tent-PSO-BP model achieves a reduction of 97.10% in Mean Squared Error (MSE) and 93.01% in Mean Absolute Error (MAE), compared to the traditional BP network; Additionally, it improves the coefficient of determination (R2) by 34.56% and the Relative Standard Deviation (RSD) by 29.38%. Comparative experimental results show that, compared with existing algorithms such as Long Short-Term Memory (LSTM), Genetic Algorithm Optimized BP (GA-BP) and Whale Optimization Algorithm Optimized BP (WOA-BP), the Tent-PSO-BP model achieves improvements in R2 by 12.01%, 11.00% and 8.80%, respectively, and enhancements in RSD by 24.51%, 32.01% and 35.92%, respectively. These results fully demonstrate the superior accuracy and stability of the Tent-PSO-BP model in predicting defect depth in civil aircraft composite materials. With the best overall performance among the evaluated methods, the model holds significant application potential in the field of infrared nondestructive testing in aviation and offers a novel research perspective for the quantitative analysis of composite material defects.
{"title":"An improved BP neural network algorithm for accurate prediction of impact defects depth in civil aircraft composite materials","authors":"Huazhong Zhang , Rong Yang , Mian Zhong , Xia Lei , Juhang Yin , Ming Yang , Xiaoguang Tu , Fei Li , Xiaoqing Xing , Chao Zhou","doi":"10.1016/j.infrared.2026.106475","DOIUrl":"10.1016/j.infrared.2026.106475","url":null,"abstract":"<div><div>To address the problems of low prediction accuracy and poor stability in traditional BP neural networks applied to quantitative defect depth evaluation of composite materials in civil aircraft, this study proposes an improved defect depth prediction model based on a BP neural network optimized using a Tent chaos enhanced Particle Swarm Optimization algorithm (Tent-PSO-BP). This algorithm integrates the PSO algorithm to effectively determine the optimal initial parameters of the network, thereby enhancing prediction accuracy. Furthermore, the Tent chaotic mapping strategy is employed to initialize the population in the PSO algorithm, ensuring a uniform distribution of initial parameters and mitigating the stability issues commonly encountered in traditional BP neural networks during prediction tasks. Results from ablation experiments demonstrates that the improved Tent-PSO-BP model achieves a reduction of 97.10% in Mean Squared Error (MSE) and 93.01% in Mean Absolute Error (MAE), compared to the traditional BP network; Additionally, it improves the coefficient of determination (R<sup>2</sup>) by 34.56% and the Relative Standard Deviation (RSD) by 29.38%. Comparative experimental results show that, compared with existing algorithms such as Long Short-Term Memory (LSTM), Genetic Algorithm Optimized BP (GA-BP) and Whale Optimization Algorithm Optimized BP (WOA-BP), the Tent-PSO-BP model achieves improvements in R<sup>2</sup> by 12.01%, 11.00% and 8.80%, respectively, and enhancements in RSD by 24.51%, 32.01% and 35.92%, respectively. These results fully demonstrate the superior accuracy and stability of the Tent-PSO-BP model in predicting defect depth in civil aircraft composite materials. With the best overall performance among the evaluated methods, the model holds significant application potential in the field of infrared nondestructive testing in aviation and offers a novel research perspective for the quantitative analysis of composite material defects.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"155 ","pages":"Article 106475"},"PeriodicalIF":3.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386274","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 : 2026-05-01Epub Date: 2026-02-12DOI: 10.1016/j.infrared.2026.106457
Jiaqi Wei , Peng Cao , Zeyu Wang , Tiancai Wang , Chunxu Song , Yidan Hu , Minghui You , Hongling Peng , Qiandong Zhuang , Wanhua Zheng
In this work, we propose a dual-passivation strategy to suppress dark current in short-wavelength infrared (SWIR) type-II superlattice (T2SL) avalanche photodiodes (APDs) featuring a separate-absorption-grading-charge-multiplication (SAGCM) architecture. It is noted that conventional single-layer dielectrics such as PECVD (Plasma Enhanced Chemical Vapor Deposition) SiO2 or ALD (Atomic Layer Deposition) Al2O3 offer only limited leakage suppression under high electric fields, making them insufficient for deeply etched devices. To mitigate this challenge, we introduce a dual-passivation layer consisting of 35-nm ALD Al2O3 and 450-nm PECVD SiO2 which effectively reduces interface traps and easing electric-field crowding along the mesa sidewall. As a result, the dark current is reduced by more than one order of magnitude, and thermal stability is improved across 120–295 K. Leakage current analysis further reveals a transition from surface-dominated to bulk-dominated transport, confirming that DPL effectively suppresses surface contributions and enables low-noise operation. Such performance indicates strong potential for reliable, high-gain SWIR T2SL APDs in practical sensing applications.
{"title":"Dark current suppression of short wavelength infrared InGaAs/GaAsSb-AlGaAsSb avalanche photodiodes by dual passivation layer","authors":"Jiaqi Wei , Peng Cao , Zeyu Wang , Tiancai Wang , Chunxu Song , Yidan Hu , Minghui You , Hongling Peng , Qiandong Zhuang , Wanhua Zheng","doi":"10.1016/j.infrared.2026.106457","DOIUrl":"10.1016/j.infrared.2026.106457","url":null,"abstract":"<div><div>In this work, we propose a dual-passivation strategy to suppress dark current in short-wavelength infrared (SWIR) type-II superlattice (T2SL) avalanche photodiodes (APDs) featuring a separate-absorption-grading-charge-multiplication (SAGCM) architecture. It is noted that conventional single-layer dielectrics such as PECVD (Plasma Enhanced Chemical Vapor Deposition) SiO<sub>2</sub> or ALD (Atomic Layer Deposition) Al<sub>2</sub>O<sub>3</sub> offer only limited leakage suppression under high electric fields, making them insufficient for deeply etched devices. To mitigate this challenge, we introduce a dual-passivation layer consisting of 35-nm ALD Al<sub>2</sub>O<sub>3</sub> and 450-nm PECVD SiO<sub>2</sub> which effectively reduces interface traps and easing electric-field crowding along the mesa sidewall. As a result, the dark current is reduced by more than one order of magnitude, and thermal stability is improved across 120–295 K. Leakage current analysis further reveals a transition from surface-dominated to bulk-dominated transport, confirming that DPL effectively suppresses surface contributions and enables low-noise operation. Such performance indicates strong potential for reliable, high-gain SWIR T2SL APDs in practical sensing applications.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"155 ","pages":"Article 106457"},"PeriodicalIF":3.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386284","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 : 2026-05-01Epub Date: 2026-02-05DOI: 10.1016/j.infrared.2026.106446
Yujun Chen, Peng Cai, Yujia Li, Hang Ming, Minnan Wu, Lei Chen, Ligang Huang, Lei Gao, Tao Zhu
Noise-like pulses (NLPs) with intense randomness play a crucial role in low-coherence spectroscopic measurements, supercontinuum generation, random laser imaging, and chaotic laser sensing. However, systematic analysis addressing both the spectral intensity randomness and the polarization characteristics of NLPs have not yet been explored. Here, we use the dispersive Fourier transform technique and the high-speed wavelength-resolved polarization measurement technique to investigate the spectral randomness and polarization characteristics of NLPs generated by nonlinear polarization rotation mode-locking in a net-normal dispersive cavity with varying lengths of highly nonlinear fiber (HNLF). Through experimental and statistical methods (correlation, Pearson coefficient, mutual information), we demonstrated that HNLF enhances spectral intensity randomness in NLPs. The incorporation of HNLF not only increases the spectral correlation decay rate but also reduces the full width at half maximum of the Pearson coefficient curve corresponding to the peak wavelength from 0.38 nm to below 0.1 nm. Accompanied by the polarization filtering effects of nonlinear polarization rotation, the wavelength-resolved states of polarization (SOP) for the NLPs exhibit partial randomness on the Poincaré sphere. We quantify polarization distribution characteristics and randomness using the relative distance (r) of SOP projection points and approximate entropy (ApEn). HNLF enhances both polarization distribution range and randomness, increasing r_max from 2 to 3 and improving ApEn values for polar/azimuthal angles at different wavelengths. The simulation result is consistent with experiments. Our work provides a systematic routine for investigating the randomness in NLPs, and also offers a new approach for generating low-cost, highly random ultrafast light sources.
{"title":"Randomness enhancement of noise-like pulses in nonlinear polarization rotation fiber cavity","authors":"Yujun Chen, Peng Cai, Yujia Li, Hang Ming, Minnan Wu, Lei Chen, Ligang Huang, Lei Gao, Tao Zhu","doi":"10.1016/j.infrared.2026.106446","DOIUrl":"10.1016/j.infrared.2026.106446","url":null,"abstract":"<div><div>Noise-like pulses (NLPs) with intense randomness play a crucial role in low-coherence spectroscopic measurements, supercontinuum generation, random laser imaging, and chaotic laser sensing. However, systematic analysis addressing both the spectral intensity randomness and the polarization characteristics of NLPs have not yet been explored. Here, we use the dispersive Fourier transform technique and the high-speed wavelength-resolved polarization measurement technique to investigate the spectral randomness and polarization characteristics of NLPs generated by nonlinear polarization rotation mode-locking in a net-normal dispersive cavity with varying lengths of highly nonlinear fiber (HNLF). Through experimental and statistical methods (correlation, Pearson coefficient, mutual information), we demonstrated that HNLF enhances spectral intensity randomness in NLPs. The incorporation of HNLF not only increases the spectral correlation decay rate but also reduces the full width at half maximum of the Pearson coefficient curve corresponding to the peak wavelength from 0.38 nm to below 0.1 nm. Accompanied by the polarization filtering effects of nonlinear polarization rotation, the wavelength-resolved states of polarization (SOP) for the NLPs exhibit partial randomness on the Poincaré sphere. We quantify polarization distribution characteristics and randomness using the relative distance (<em>r</em>) of SOP projection points and approximate entropy (ApEn). HNLF enhances both polarization distribution range and randomness, increasing <em>r_max</em> from 2 to 3 and improving ApEn values for polar/azimuthal angles at different wavelengths. The simulation result is consistent with experiments. Our work provides a systematic routine for investigating the randomness in NLPs, and also offers a new approach for generating low-cost, highly random ultrafast light sources.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"155 ","pages":"Article 106446"},"PeriodicalIF":3.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172813","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 : 2026-05-01Epub Date: 2026-02-03DOI: 10.1016/j.infrared.2026.106444
Anhong Tian , Bo Yan , Chengbiao Fu
To explore the effects of fractional-order derivative (FOD) implementation strategies and key parameters on Vis–NIR hyperspectral modeling for soil nickel (Ni) content prediction, this study focused on contaminated farmland soil in Mojiang Hani Autonomous County, Yunnan Province, China. Twelve modeling pipelines were designed, combining two FOD implementation strategies (fixed-window FOD and full-history FOD), two feature band selection strategies (the correlation coefficient method and full-spectrum bands), and four regression algorithms (PLSR, SVR, BPNN, and GRNN). The results showed the following: (1) The impact of fixed-window FOD on hyperspectral preprocessing and subsequent modeling performance was non-monotonic with window size; appropriate window sizes helped mitigate potential information redundancy and imbalance associated with full-history FOD while reducing preprocessing time. (2) Compared with integer-order derivative (IOD) preprocessing, FOD preprocessing (both fixed-window and full-history) was more effective in improving the predictive performance of models for soil Ni prediction. (3) The optimal model under fixed-window FOD (GRNN, window size = 80, order = 0.95) achieved RPD = 2.74, R2 = 0.87, and RMSE = 97.76 mg/kg on the validation set. For full-history FOD, the best model (BPNN, order = 0.7) yielded RPD = 2.56, R2 = 0.85, and RMSE = 104.66 mg/kg.
{"title":"Fractional-order derivative coupled machine learning models for quantitative prediction of soil Ni content","authors":"Anhong Tian , Bo Yan , Chengbiao Fu","doi":"10.1016/j.infrared.2026.106444","DOIUrl":"10.1016/j.infrared.2026.106444","url":null,"abstract":"<div><div>To explore the effects of fractional-order derivative (FOD) implementation strategies and key parameters on Vis–NIR hyperspectral modeling for soil nickel (Ni) content prediction, this study focused on contaminated farmland soil in Mojiang Hani Autonomous County, Yunnan Province, China. Twelve modeling pipelines were designed, combining two FOD implementation strategies (fixed-window FOD and full-history FOD), two feature band selection strategies (the correlation coefficient method and full-spectrum bands), and four regression algorithms (PLSR, SVR, BPNN, and GRNN). The results showed the following: (1) The impact of fixed-window FOD on hyperspectral preprocessing and subsequent modeling performance was non-monotonic with window size; appropriate window sizes helped mitigate potential information redundancy and imbalance associated with full-history FOD while reducing preprocessing time. (2) Compared with integer-order derivative (IOD) preprocessing, FOD preprocessing (both fixed-window and full-history) was more effective in improving the predictive performance of models for soil Ni prediction. (3) The optimal model under fixed-window FOD (GRNN, window size = 80, order = 0.95) achieved RPD = 2.74, R<sup>2</sup> = 0.87, and RMSE = 97.76 mg/kg on the validation set. For full-history FOD, the best model (BPNN, order = 0.7) yielded RPD = 2.56, R<sup>2</sup> = 0.85, and RMSE = 104.66 mg/kg.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"155 ","pages":"Article 106444"},"PeriodicalIF":3.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386276","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 : 2026-05-01Epub Date: 2026-03-04DOI: 10.1016/j.infrared.2026.106492
Wenting Liu , Xinming Lu , Jianxin Zhang , Shengzhe Hou , Tianyu Zhang
Infrared small target detection (IRSTD) is a critical technology in modern early warning and sensing systems. Existing single-frame detection methods rely solely on spatial domain information and struggle to effectively distinguish targets from background clutter in complex scenarios. While multi-frame detection methods introduce temporal cues to enhance detection performance, they still exhibit limitations in spatio-temporal feature extraction and fusion strategies. To overcome these challenges, we propose a novel Dual-Stream Spatio-Temporal Cross Attention Network (DSCA-Net). Specifically, we first design a Dual-Stream Feature Extractor (DSFE) that employs parallel 3D and 2D convolutional networks to extract temporal motion information and spatial detail features, respectively, effectively achieving decoupled representation of spatio-temporal features. Second, we introduce a Temporal Attention (TA) module that employs an adaptive weighting mechanism to dynamically enhance motion responses at critical moments, significantly improving the network’s perception capability for target motion characteristics. Finally, we construct a Spatio-Temporal Cross-Attention Fusion (STCAF) module that achieves deep interactive fusion between static spatial features and dynamic motion features through standard cross-attention and position-guided cross-attention mechanisms. Systematic evaluation on three public datasets demonstrates that the proposed DSCA-Net achieves competitive performance compared to mainstream methods, with particularly notable improvements on the IRDST dataset, validating its effectiveness in complex scenes.
{"title":"A dual-stream spatio-temporal cross attention network for moving infrared dim and small target detection","authors":"Wenting Liu , Xinming Lu , Jianxin Zhang , Shengzhe Hou , Tianyu Zhang","doi":"10.1016/j.infrared.2026.106492","DOIUrl":"10.1016/j.infrared.2026.106492","url":null,"abstract":"<div><div>Infrared small target detection (IRSTD) is a critical technology in modern early warning and sensing systems. Existing single-frame detection methods rely solely on spatial domain information and struggle to effectively distinguish targets from background clutter in complex scenarios. While multi-frame detection methods introduce temporal cues to enhance detection performance, they still exhibit limitations in spatio-temporal feature extraction and fusion strategies. To overcome these challenges, we propose a novel <strong>D</strong>ual-<strong>S</strong>tream Spatio-Temporal <strong>C</strong>ross <strong>A</strong>ttention Network (DSCA-Net). Specifically, we first design a Dual-Stream Feature Extractor (DSFE) that employs parallel 3D and 2D convolutional networks to extract temporal motion information and spatial detail features, respectively, effectively achieving decoupled representation of spatio-temporal features. Second, we introduce a Temporal Attention (TA) module that employs an adaptive weighting mechanism to dynamically enhance motion responses at critical moments, significantly improving the network’s perception capability for target motion characteristics. Finally, we construct a Spatio-Temporal Cross-Attention Fusion (STCAF) module that achieves deep interactive fusion between static spatial features and dynamic motion features through standard cross-attention and position-guided cross-attention mechanisms. Systematic evaluation on three public datasets demonstrates that the proposed DSCA-Net achieves competitive performance compared to mainstream methods, with particularly notable improvements on the IRDST dataset, validating its effectiveness in complex scenes.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"155 ","pages":"Article 106492"},"PeriodicalIF":3.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386175","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}
Temperature tunable narrowband laser oscillations at 5 µm wavelength region were obtained in Tb-doped chalcogenide glass fiber due to feedback from the Bragg grating inscribed in it. The technique for direct laser writing of Bragg gratings in high refractive index chalcogenide fibers involves immersing the fiber into low-melting glass and helical motion of the lenticular beam waist of the femtosecond laser.
{"title":"5-μm Tb3+ doped chalcogenide glass fiber laser with Bragg grating","authors":"V.V. Koltashev , M.V. Sukhanov , V.V. Likhov , B.I. Denker , B.I. Galagan , S.E. Sverchkov , E.N. Lashmanov , A.P. Velmuzhov , V.G. Plotnichenko , A.G. Okhrimchuk","doi":"10.1016/j.infrared.2026.106455","DOIUrl":"10.1016/j.infrared.2026.106455","url":null,"abstract":"<div><div>Temperature tunable narrowband laser oscillations at 5 µm wavelength region were obtained in Tb-doped chalcogenide glass fiber due to feedback from the Bragg grating inscribed in it. The technique for direct laser writing of Bragg gratings in high refractive index chalcogenide fibers involves immersing the fiber into low-melting glass and helical motion of the lenticular beam waist of the femtosecond laser.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"155 ","pages":"Article 106455"},"PeriodicalIF":3.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172871","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号