Pub Date : 2024-10-04DOI: 10.1016/j.infrared.2024.105579
Lei Huang , Junrui Zhang , Qingli Zhang , Guihua Sun , Renqin Dou , Xiaofei Wang , Deming Zhang , Jinyun Gao , Yu Sun , Wenpeng Liu , Jianqiao Luo
Tm,Ho:GdScO3 single crystal was grown by the Czochralski method. Its quality and effective segregation coefficient of crystal were characterized, and spectral properties of crystal (1 0 0) plane were studied. The absorption cross-section of Tm,Ho:GdScO3 at 793 nm is 1.61 × 10−20 cm2 and emission cross-section at 2020 nm is 1.39 × 10−20 cm2. The laser performance of the crystal by 793 nm LD end-pumped was investigated. The maximum output power of 240 mW was obtained with a slope efficiency of 9.1 % in CW(continuous wave) pump mode. In pulse mode, the maximum average output power of 507 mW was achieved. The maximum slope efficiency of 13.7 % was obtained with 100 Hz and 400 μs. The laser wavelength was 2096 nm. The beam quality factors Mx2/My2 were fitted to be 1.81/1.80. These results indicate that Tm,Ho:GdScO3 crystal is a promising candidate medium for near-infrared laser application.
{"title":"Crystal growth, spectra and laser properties of Tm3+ and Ho3+ co-doped GdScO3 crystal","authors":"Lei Huang , Junrui Zhang , Qingli Zhang , Guihua Sun , Renqin Dou , Xiaofei Wang , Deming Zhang , Jinyun Gao , Yu Sun , Wenpeng Liu , Jianqiao Luo","doi":"10.1016/j.infrared.2024.105579","DOIUrl":"10.1016/j.infrared.2024.105579","url":null,"abstract":"<div><div>Tm,Ho:GdScO<sub>3</sub> single crystal was grown by the Czochralski method. Its quality and effective segregation coefficient of crystal were characterized, and spectral properties of crystal (1<!--> <!-->0<!--> <!-->0) plane were studied. The absorption cross-section of Tm,Ho:GdScO<sub>3</sub> at 793 nm is 1.61 × 10<sup>−20</sup> cm<sup>2</sup> and emission cross-section at 2020 nm is 1.39 × 10<sup>−20</sup> cm<sup>2</sup>. The laser performance of the crystal by 793 nm LD end-pumped was investigated. The maximum output power of 240 mW was obtained with a slope efficiency of 9.1 % in CW(continuous wave) pump mode. In pulse mode, the maximum average output power of 507 mW was achieved. The maximum slope efficiency of 13.7 % was obtained with 100 Hz and 400 μs. The laser wavelength was 2096 nm. The beam quality factors <em>M<sub>x</sub></em><sup>2</sup>/<em>M<sub>y</sub></em><sup>2</sup> were fitted to be 1.81/1.80. These results indicate that Tm,Ho:GdScO<sub>3</sub> crystal is a promising candidate medium for near-infrared laser application.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"143 ","pages":"Article 105579"},"PeriodicalIF":3.1,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531964","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 : 2024-10-04DOI: 10.1016/j.infrared.2024.105577
Jian-Hong Wu , Yu-Han Hu , Qi Bian , Yong Bo , Da-Fu Cui , Qin-Jun Peng
A high-power diode-pumped 2.09 μm Tm,Ho:YAG laser oscillator with multi-regime operation is demonstrated. In the continuous-wave (CW) regime, it delivers 44.68 W output power with M2 = 3.47, yielding a record-high brightness of 87.57 MW/cm2·sr. In the Q-switched mode, stable laser performance across pulse repetition frequencies (PRFs) from 1 kHz to 4 kHz is achieved. At a PRF of 1 kHz, single pulse energy reaches 22.85 mJ with a pulse width of 443.4 ns and M2 = 3.50. In the quasi-continuous-wave (QCW) operation, a pulse energy of 31.85 mJ is obtained at 200 Hz with a 370 μs pulse width and M2 = 4.49. These pulse energies are the highest reported to date for Tm-Ho co-doped laser oscillators at high PRF. This also marks the first demonstration of a versatile 2 μm laser that can operate at room temperature while delivering high-energy, high-repetition-rate pulses in both nanosecond and microsecond durations within a single device, making it highly appealing for scientific and industrial applications.
{"title":"High power continuous-wave, Q-switched, and quasi-continuous-wave operation of a diode-pumped Tm,Ho:YAG laser oscillator at 2.09 μm","authors":"Jian-Hong Wu , Yu-Han Hu , Qi Bian , Yong Bo , Da-Fu Cui , Qin-Jun Peng","doi":"10.1016/j.infrared.2024.105577","DOIUrl":"10.1016/j.infrared.2024.105577","url":null,"abstract":"<div><div>A high-power diode-pumped 2.09 μm Tm,Ho:YAG laser oscillator with multi-regime operation is demonstrated. In the continuous-wave (CW) regime, it delivers 44.68 W output power with <em>M<sup>2</sup></em> = 3.47, yielding a record-high brightness of 87.57 MW/cm<sup>2</sup>·sr. In the Q-switched mode, stable laser performance across pulse repetition frequencies (PRFs) from 1 kHz to 4 kHz is achieved. At a PRF of 1 kHz, single pulse energy reaches 22.85 mJ with a pulse width of 443.4 ns and <em>M<sup>2</sup></em> = 3.50. In the quasi-continuous-wave (QCW) operation, a pulse energy of 31.85 mJ is obtained at 200 Hz with a 370 μs pulse width and <em>M<sup>2</sup></em> = 4.49. These pulse energies are the highest reported to date for Tm-Ho co-doped laser oscillators at high PRF. This also marks the first demonstration of a versatile 2 μm laser that can operate at room temperature while delivering high-energy, high-repetition-rate pulses in both nanosecond and microsecond durations within a single device, making it highly appealing for scientific and industrial applications.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"142 ","pages":"Article 105577"},"PeriodicalIF":3.1,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425973","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 : 2024-10-04DOI: 10.1016/j.infrared.2024.105567
Hermes A. Tenorio-Tamayo, Sandra E. Nope-Rodríguez, Humberto Loaiza-Correa, Andrés D. Restrepo-Girón
A method for the detection of plastic anti-personnel mines called “ leg breakers ” is presented from images of the ground acquired remotely by a drone at heights between 1 and 5 m. The proposal achieved an accuracy of 92.13 % and a sensitivity of 82.4 % when evaluating the performance on 260 test images, a number higher than that used in previous works, and with mines buried in real terrain with the presence of vegetation. The above on images acquired on different dates with different environmental conditions and soil moisture. In addition, it was found that the method was adapted to three different thermographic cameras, being necessary only to adjust the gamma parameter associated with the thermal contrast enhancement technique used. It was corroborated that mines are easier to detect to the extent that they are buried more superficially, and when the flight height of the drone is between 1 and 2 m. Finally, it is highlighted that the proposal has the potential to be executed in processing systems onboard the drone, thanks to its algorithmic simplicity.
{"title":"Detection of anti-personnel mines of the “leg breakers” type by analyzing thermographic images captured from a drone at different heights","authors":"Hermes A. Tenorio-Tamayo, Sandra E. Nope-Rodríguez, Humberto Loaiza-Correa, Andrés D. Restrepo-Girón","doi":"10.1016/j.infrared.2024.105567","DOIUrl":"10.1016/j.infrared.2024.105567","url":null,"abstract":"<div><div>A method for the detection of plastic anti-personnel mines called “ leg breakers ” is presented from images of the ground acquired remotely by a drone at heights between 1 and 5 m. The proposal achieved an accuracy of 92.13 % and a sensitivity of 82.4 % when evaluating the performance on 260 test images, a number higher than that used in previous works, and with mines buried in real terrain with the presence of vegetation. The above on images acquired on different dates with different environmental conditions and soil moisture. In addition, it was found that the method was adapted to three different thermographic cameras, being necessary only to adjust the gamma parameter associated with the thermal contrast enhancement technique used. It was corroborated that mines are easier to detect to the extent that they are buried more superficially, and when the flight height of the drone is between 1 and 2 m. Finally, it is highlighted that the proposal has the potential to be executed in processing systems onboard the drone, thanks to its algorithmic simplicity.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"142 ","pages":"Article 105567"},"PeriodicalIF":3.1,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-02DOI: 10.1016/j.infrared.2024.105576
Dan Wu, Yifan Wang, Zhifei Miao, Chenghao Wu
Post-processing of the infrared thermography image is crucial for nondestructive testing, which will reduce noise and disturbance considerably. In this work, an improved image post-processing method based on the temperature ratio is proposed, namely the Thermal Image Division (TID) method. To validate this method, we carried out experiments on different materials such as composite CFRP (carbon fiber reinforced polymer) plates, 304 stainless steel plates and aluminum alloy samples. The results show the proposed method is pretty useful, significantly improves the signal-to-noise ratio of the image by comparing with other post-processing methods. It’s not only beneficial for identifying the edge of the defect, but also facilitates the detection of smaller defects with deeper depth. The signal-to-noise ratio is improved by nearly 117.5 % from practice. The TID method was applied to the defect size detection of pulse thermography and ultrasonic thermography. The results indicate TID method has good robustness, significantly reduces the error of defect size quantification.
红外热成像图像的后处理对于无损检测至关重要，它将大大减少噪声和干扰。在这项工作中，我们提出了一种基于温度比的改进图像后处理方法，即热图像分割（TID）方法。为了验证这种方法，我们在不同材料上进行了实验，如复合 CFRP（碳纤维增强聚合物）板、304 不锈钢板和铝合金样品。结果表明，与其他后处理方法相比，所提出的方法非常有用，能显著提高图像的信噪比。它不仅有利于识别缺陷边缘，还有利于检测深度较深的较小缺陷。与实践相比，信噪比提高了近 117.5%。TID 方法被应用于脉冲热成像和超声热成像的缺陷尺寸检测。结果表明 TID 方法具有良好的鲁棒性，能显著降低缺陷尺寸量化的误差。
{"title":"An improved infrared image post-processing method for metals and composites","authors":"Dan Wu, Yifan Wang, Zhifei Miao, Chenghao Wu","doi":"10.1016/j.infrared.2024.105576","DOIUrl":"10.1016/j.infrared.2024.105576","url":null,"abstract":"<div><div>Post-processing of the infrared thermography image is crucial for nondestructive testing, which will reduce noise and disturbance considerably. In this work, an improved image post-processing method based on the temperature ratio is proposed, namely the Thermal Image Division (TID) method. To validate this method, we carried out experiments on different materials such as composite CFRP (carbon fiber reinforced polymer) plates, 304 stainless steel plates and aluminum alloy samples. The results show the proposed method is pretty useful, significantly improves the signal-to-noise ratio of the image by comparing with other post-processing methods. It’s not only beneficial for identifying the edge of the defect, but also facilitates the detection of smaller defects with deeper depth. The signal-to-noise ratio is improved by nearly 117.5 % from practice. The TID method was applied to the defect size detection of pulse thermography and ultrasonic thermography. The results indicate TID method has good robustness, significantly reduces the error of defect size quantification.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"142 ","pages":"Article 105576"},"PeriodicalIF":3.1,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425971","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}
This paper proposes a method for discriminating between normal apples and watercore apples using visible/near-infrared spectroscopy technology, which combines Gramian Angular Fields (GAF) encoding technology and the ConvNeXt deep learning network. The existing feature extraction methods for visible/near-infrared spectroscopy data do not perform deeper information mining on the extracted features, which results in the quality of the established model being entirely determined by the extracted features. Additionally, the process of building a visible/near-infrared spectroscopy data classification model is complex and time-consuming, and the accuracy of the established model is not high. To address these issues, the experimental visible/near-infrared spectroscopy data of apples was first transformed into two-dimensional images using Gramian Angular Summation Fields (GASF) and Gramian Angular Difference Fields (GADF) with sizes of 64, 128, 256, and 512. These images were then input into the ConvNeXt network, and the performance of different encoding methods and sizes was compared. The results showed that, under the conditions provided in this paper, the GADF encoding method with a size of 256 achieved the highest classification accuracy of 98.48%. Next, ResNet, EfficientNet, and RegNet deep learning networks were selected to classify the encoded images under the same conditions. The results above indicate that the apple variety discrimination method based on GAF encoding technology and ConvNeXt network combined with visible/near-infrared spectroscopy technology can achieve deep information mining of visible/near-infrared spectroscopy data and provide a relatively simple method for establishing qualitative classification models of visible/near-infrared spectroscopy. This method has a relatively excellent discrimination effect between normal apples and watercore apples.
{"title":"Identification of apple watercore based on ConvNeXt and Vis/NIR spectra","authors":"Chunlin Zhao , Zhipeng Yin , Wenbin Zhang , Panpan Guo , Yaxing Ma","doi":"10.1016/j.infrared.2024.105575","DOIUrl":"10.1016/j.infrared.2024.105575","url":null,"abstract":"<div><div>This paper proposes a method for discriminating between normal apples and watercore apples using visible/near-infrared spectroscopy technology, which combines Gramian Angular Fields (GAF) encoding technology and the ConvNeXt deep learning network. The existing feature extraction methods for visible/near-infrared spectroscopy data do not perform deeper information mining on the extracted features, which results in the quality of the established model being entirely determined by the extracted features. Additionally, the process of building a visible/near-infrared spectroscopy data classification model is complex and time-consuming, and the accuracy of the established model is not high. To address these issues, the experimental visible/near-infrared spectroscopy data of apples was first transformed into two-dimensional images using Gramian Angular Summation Fields (GASF) and Gramian Angular Difference Fields (GADF) with sizes of 64, 128, 256, and 512. These images were then input into the ConvNeXt network, and the performance of different encoding methods and sizes was compared. The results showed that, under the conditions provided in this paper, the GADF encoding method with a size of 256 achieved the highest classification accuracy of 98.48%. Next, ResNet, EfficientNet, and RegNet deep learning networks were selected to classify the encoded images under the same conditions. The results above indicate that the apple variety discrimination method based on GAF encoding technology and ConvNeXt network combined with visible/near-infrared spectroscopy technology can achieve deep information mining of visible/near-infrared spectroscopy data and provide a relatively simple method for establishing qualitative classification models of visible/near-infrared spectroscopy. This method has a relatively excellent discrimination effect between normal apples and watercore apples.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"142 ","pages":"Article 105575"},"PeriodicalIF":3.1,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432140","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}
In this paper, we present, for the first time, a bulk LiNbO3 (LN) acousto-optic (AO) Q-switched Er:YAP laser operating at a pulse repetition frequency (PRF) of 1 kHz. At this frequency, the laser achieves a maximum single pulse energy of 0.34 mJ, with a corresponding pulse duration of 64.5 ns and a peak power of 5.3 kW. Additionally, we characterize the laser beam quality factors, = 2.7 and = 2.5, and its central wavelength at 2730.7 nm, all at 1 kHz. These results highlight the significant potential of LN AO Q-switched Er:YAP lasers for enhancing mid-infrared laser applications.
{"title":"1 kHz, 5.3 kW peak power pulse generation from a LiNbO3 acousto-optically Q-switched Er:YAP laser","authors":"Runming Zhang, Baoquan Yao, Disheng Wei, Junhui Li, Jinwen Tang, Wenhao Cheng, Minglang Wu, Tongyu Dai, Xiaoming Duan, Youlun Ju","doi":"10.1016/j.infrared.2024.105573","DOIUrl":"10.1016/j.infrared.2024.105573","url":null,"abstract":"<div><div>In this paper, we present, for the first time, a bulk LiNbO<sub>3</sub> (LN) acousto-optic (AO) Q-switched Er:YAP laser operating at a pulse repetition frequency (PRF) of 1 kHz. At this frequency, the laser achieves a maximum single pulse energy of 0.34 mJ, with a corresponding pulse duration of 64.5 ns and a peak power of 5.3 kW. Additionally, we characterize the laser beam quality factors, <span><math><mrow><msubsup><mi>M</mi><mrow><mi>x</mi></mrow><mn>2</mn></msubsup></mrow></math></span> = 2.7 and <span><math><mrow><msubsup><mi>M</mi><mrow><mi>y</mi></mrow><mn>2</mn></msubsup></mrow></math></span> = 2.5, and its central wavelength at 2730.7 nm, all at 1 kHz. These results highlight the significant potential of LN AO Q-switched Er:YAP lasers for enhancing mid-infrared laser applications.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"142 ","pages":"Article 105573"},"PeriodicalIF":3.1,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425970","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 : 2024-09-30DOI: 10.1016/j.infrared.2024.105566
Yiwei He , Chunlei Yu , Yizhen Yu , Jingxian Bao , Bo Yang , Xue Li
The serial resistor of alloy material can be integrated on negative feedback avalanche diodes to reduce afterpulsing effect. In this work, the influence of parasitic capacitance on the avalanche quenching resistor was theoretically analyzed. By using simulation model of device & circuit mixed-mode, the quenching capability of integrated resistors was evaluated with the parasitic parameters. For the material growth of feedback quenching resistor, thin film based on CrSi alloy was prepared by ion beam sputtering process, realizing the sheet resistance of 3 kΩ/square. The resistor material were sufficiently investigated by characterizing the morphology and element component. CrSi pattern of spiral shape was fabricated on sapphire substrate, realizing a resistor of the order of 500 kΩ in area of diameter 40 μm, which was equivalent to the active area of avalanche diodes. The electrical measurement indicated the excellent temperature stability of this integrated resistor, showing the promising application prospect for preparing high-performance negative feedback avalanche diodes.
{"title":"Design and fabrication of integrated negative feedback resistor for InGaAs/InP avalanche photodiode","authors":"Yiwei He , Chunlei Yu , Yizhen Yu , Jingxian Bao , Bo Yang , Xue Li","doi":"10.1016/j.infrared.2024.105566","DOIUrl":"10.1016/j.infrared.2024.105566","url":null,"abstract":"<div><div>The serial resistor of alloy material can be integrated on negative feedback avalanche diodes to reduce afterpulsing effect. In this work, the influence of parasitic capacitance on the avalanche quenching resistor was theoretically analyzed. By using simulation model of device & circuit mixed-mode, the quenching capability of integrated resistors was evaluated with the parasitic parameters. For the material growth of feedback quenching resistor, thin film based on CrSi alloy was prepared by ion beam sputtering process, realizing the sheet resistance of 3 kΩ/square. The resistor material were sufficiently investigated by characterizing the morphology and element component. CrSi pattern of spiral shape was fabricated on sapphire substrate, realizing a resistor of the order of 500 kΩ in area of diameter 40 μm, which was equivalent to the active area of avalanche diodes. The electrical measurement indicated the excellent temperature stability of this integrated resistor, showing the promising application prospect for preparing high-performance negative feedback avalanche diodes.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"142 ","pages":"Article 105566"},"PeriodicalIF":3.1,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425904","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 : 2024-09-30DOI: 10.1016/j.infrared.2024.105574
Sizhi Xu , Yubo Gao , Xing Liu , Zuoyuan Ou , Fayyaz Javed , Xiaoyang Guo , Di Lin , Xingyu He , Haotian Lu , Junzhan Chen , Chunyu Guo , Cangtao Zhou , Qitao Lue , Shuangchen Ruan
We experimentally demonstrated a compact, highly efficient, stable, chirped pulse amplification (CPA) thin-disk regenerative system with a tunable repetition rate. The laser head consists of a 9 at. % Yb:YAG thin-disk with a diameter of 8.8 mm and a thickness of 150 μm, is designed for a 48-pump pass configuration. In CPA-based regenerative amplifier configuration, a maximal output power of 85 W at 500 kHz is achieved with a conversion efficiency of 53.1 %. This corresponds to a pulse energy of 170 μJ. To the best of our knowledge, this is the highest conversion efficiency in CPA thin-disk regenerative amplifiers. The pulse width is compressed to 884 fs with a pair of grating, resulting in a peak power of 192 MW. At 85 W, a near diffraction limit beam quality factor M2 of 1.40 is measured, which is essential in precision applications. In addition, remarkable long-term power stability is confirmed with a root-mean-square (RMS) fluctuation of 0.12 % over a 24-hour duration. The reported femtosecond amplifier is believed to be a promising tool for various applications such as extreme manufacturing, terahertz spectroscopy, etc.
{"title":"High-efficiency Yb:YAG thin-disk chirped pulse amplifier delivering 884-femtosecond laser with tunable repetition rates and high stability","authors":"Sizhi Xu , Yubo Gao , Xing Liu , Zuoyuan Ou , Fayyaz Javed , Xiaoyang Guo , Di Lin , Xingyu He , Haotian Lu , Junzhan Chen , Chunyu Guo , Cangtao Zhou , Qitao Lue , Shuangchen Ruan","doi":"10.1016/j.infrared.2024.105574","DOIUrl":"10.1016/j.infrared.2024.105574","url":null,"abstract":"<div><div>We experimentally demonstrated a compact, highly efficient, stable, chirped pulse amplification (CPA) thin-disk regenerative system with a tunable repetition rate. The laser head consists of a 9 at. % Yb:YAG thin-disk with a diameter of 8.8 mm and a thickness of 150 μm, is designed for a 48-pump pass configuration. In CPA-based regenerative amplifier configuration, a maximal output power of 85 W at 500 kHz is achieved with a conversion efficiency of 53.1 %. This corresponds to a pulse energy of 170 μJ. To the best of our knowledge, this is the highest conversion efficiency in CPA thin-disk regenerative amplifiers. The pulse width is compressed to 884 fs with a pair of grating, resulting in a peak power of 192 MW. At 85 W, a near diffraction limit beam quality factor M<sup>2</sup> of 1.40 is measured, which is essential in precision applications. In addition, remarkable long-term power stability is confirmed with a root-mean-square (RMS) fluctuation of 0.12 % over a 24-hour duration. The reported femtosecond amplifier is believed to be a promising tool for various applications such as extreme manufacturing, terahertz spectroscopy, etc.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"142 ","pages":"Article 105574"},"PeriodicalIF":3.1,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425966","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 : 2024-09-29DOI: 10.1016/j.infrared.2024.105568
Yang Wang , Yongao Zhao , Xu Zhang , Yufeng Zhang , Jingmin Dai
Reducing the operating temperature of electronic components is an effective method for enhancing their performance. Selecting suitable thermal management materials is crucial for optimizing cooling efficiency. Normal spectral emissivity, a dimensionless physical quantity, is key in assessing a material’s capability for radiative cooling. This paper outlines the construction of a reflective infrared emissivity measurement apparatus using the IS-50 Fourier Transform Infrared Spectrometer. A gold-coated diffuse integrating sphere was strategically placed in the spectrometer’s sample chamber. By ingeniously leveraging the spectrometer’s original optical path, a dual-sided gold-coated mirror was employed to capture both incident and reflected light, enabling accurate measurements of the normal spectral emissivity of materials used for cooling electronic components. The measurement results for typical materials were consistent with those reported in the literature, satisfyingly so. The uncertainty of the measurement setup was thoroughly evaluated, achieving a combined uncertainty of better than 1 %. This experimental study measured the normal spectral emissivity of various thermal management materials and analyzed the influence of temperature on normal spectral emissivity. These results provide crucial data support for thermal design, simulation analysis, and temperature monitoring in the development of thermal structures for electronic components.
{"title":"Normal spectral emissivity measurement of thermal management materials for electronic components in the 2–14 μm range","authors":"Yang Wang , Yongao Zhao , Xu Zhang , Yufeng Zhang , Jingmin Dai","doi":"10.1016/j.infrared.2024.105568","DOIUrl":"10.1016/j.infrared.2024.105568","url":null,"abstract":"<div><div>Reducing the operating temperature of electronic components is an effective method for enhancing their performance. Selecting suitable thermal management materials is crucial for optimizing cooling efficiency. Normal spectral emissivity, a dimensionless physical quantity, is key in assessing a material’s capability for radiative cooling. This paper outlines the construction of a reflective infrared emissivity measurement apparatus using the IS-50 Fourier Transform Infrared Spectrometer. A gold-coated diffuse integrating sphere was strategically placed in the spectrometer’s sample chamber. By ingeniously leveraging the spectrometer’s original optical path, a dual-sided gold-coated mirror was employed to capture both incident and reflected light, enabling accurate measurements of the normal spectral emissivity of materials used for cooling electronic components. The measurement results for typical materials were consistent with those reported in the literature, satisfyingly so. The uncertainty of the measurement setup was thoroughly evaluated, achieving a combined uncertainty of better than 1 %. This experimental study measured the normal spectral emissivity of various thermal management materials and analyzed the influence of temperature on normal spectral emissivity. These results provide crucial data support for thermal design, simulation analysis, and temperature monitoring in the development of thermal structures for electronic components.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"142 ","pages":"Article 105568"},"PeriodicalIF":3.1,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425906","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}
Pecans are essential nuts containing polyunsaturated fatty acids and dietary fiber which offer health benefits to humans. They are exported and sold in both in-shell and shelled forms. However, varietal identification poses a challenge to both producers and processors, which results in variety substitution for economic advantages. The aim of this study was to investigate the efficacy of visible near-infrared (VNIR) and near-infrared (NIR) hyperspectral imaging systems (HSI) to accurately identify pecan cultivars (Cape fear, Desirable, Stuart blend, and Sumner). The in-shell and shelled spectra were acquired using VNIR and NIR-HSI at wavelengths 400–1000 nm and 900–1700 nm, respectively. The spectra dimensionality was reduced using principal component analysis (PCA). Thereafter, the selected principal components (PCs) were used to build six machine learning classifiers (Decision Tree, Random Forest, Gradient Boosting, Partial Least Square Discriminant Analysis, Support Vector Machine, and Linear Discriminant Analysis (LDA)) for four-class classification. LDA with and without PCA achieved the highest accuracy for both pecan forms. For shelled pecans, the LDA without PCA achieved 90.59 % and increased to 91.67 % accuracy with PCA on the VNIR spectra, while the LDA without PCA achieved 93.36 % and increased to 93.52 % accuracy with PCA on the NIR spectra. For the in-shell pecans, LDA without PCA achieved 98.59 % and increased to 99.12 % accuracy with PCA on the VNIR spectra, while LDA with and without PCA achieved 98.26 % accuracy for the NIR spectra. Moreover, Successive Projection Algorithm was also implemented for wavelength selection and modeling with satisfactory results. Overall, higher accuracy was achieved in the in-shell pecan. This study revealed the usefulness of HSI systems in identifying pecan varieties.
{"title":"Precision variety identification of shelled and in-shell pecans using hyperspectral imaging with machine learning","authors":"Ebenezer Olaniyi , Christopher Kucha , Priyanka Dahiya , Allison Niu","doi":"10.1016/j.infrared.2024.105570","DOIUrl":"10.1016/j.infrared.2024.105570","url":null,"abstract":"<div><div>Pecans are essential nuts containing polyunsaturated fatty acids and dietary fiber which offer health benefits to humans. They are exported and sold in both in-shell and shelled forms. However, varietal identification poses a challenge to both producers and processors, which results in variety substitution for economic advantages. The aim of this study was to investigate the efficacy of visible near-infrared (VNIR) and near-infrared (NIR) hyperspectral imaging systems (HSI) to accurately identify pecan cultivars (Cape fear, Desirable, Stuart blend, and Sumner). The in-shell and shelled spectra were acquired using VNIR and NIR-HSI at wavelengths 400–1000 nm and 900–1700 nm, respectively. The spectra dimensionality was reduced using principal component analysis (PCA). Thereafter, the selected principal components (PCs) were used to build six machine learning classifiers (Decision Tree, Random Forest, Gradient Boosting, Partial Least Square Discriminant Analysis, Support Vector Machine, and Linear Discriminant Analysis (LDA)) for four-class classification. LDA with and without PCA achieved the highest accuracy for both pecan forms. For shelled pecans, the LDA without PCA achieved 90.59 % and increased to 91.67 % accuracy with PCA on the VNIR spectra, while the LDA without PCA achieved 93.36 % and increased to 93.52 % accuracy with PCA on the NIR spectra. For the in-shell pecans, LDA without PCA achieved 98.59 % and increased to 99.12 % accuracy with PCA on the VNIR spectra, while LDA with and without PCA achieved 98.26 % accuracy for the NIR spectra. Moreover, Successive Projection Algorithm was also implemented for wavelength selection and modeling with satisfactory results. Overall, higher accuracy was achieved in the in-shell pecan. This study revealed the usefulness of HSI systems in identifying pecan varieties.</div></div>","PeriodicalId":13549,"journal":{"name":"Infrared Physics & Technology","volume":"142 ","pages":"Article 105570"},"PeriodicalIF":3.1,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425969","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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