Pub Date : 2024-10-15DOI: 10.1016/j.optlastec.2024.111959
Zhen Yi , Zhihao Zhang , Jianglin Guan , Guanghui Zhao , Renhong Gao , Botao Fu , Jintian Lin , Jinming Chen , Jian Liu , Yijie Pan , Ya Cheng
We demonstrate an on-chip lithium niobate micro-disk laser based on hydrogen cyanide (H13C14N) gas saturation absorption method for frequency stabilization. The laser chip consists of two main components: a micro-disk laser and a combined racetrack ring cavity. By operating on the H13C14N P12 absorption line at 1551.3 nm, the laser frequency can be precisely stabilized. The laser demonstrates remarkable stability, achieving a best stability value of 9.07 × 10−9. Furthermore, the short-term stability, evaluated over continuous time intervals of 35 s, showcases exceptional performance. Additionally, the residual drift remains well below 30 MHz.
{"title":"Frequency stabilization based on H13C14N absorption in lithium niobate micro-disk laser","authors":"Zhen Yi , Zhihao Zhang , Jianglin Guan , Guanghui Zhao , Renhong Gao , Botao Fu , Jintian Lin , Jinming Chen , Jian Liu , Yijie Pan , Ya Cheng","doi":"10.1016/j.optlastec.2024.111959","DOIUrl":"10.1016/j.optlastec.2024.111959","url":null,"abstract":"<div><div>We demonstrate an on-chip lithium niobate micro-disk laser based on hydrogen cyanide (H<sub>13</sub>C<sub>14</sub>N) gas saturation absorption method for frequency stabilization. The laser chip consists of two main components: a micro-disk laser and a combined racetrack ring cavity. By operating on the H<sub>13</sub>C<sub>14</sub>N P12 absorption line at 1551.3 nm, the laser frequency can be precisely stabilized. The laser demonstrates remarkable stability, achieving a best stability value of 9.07 × 10<sup>−9</sup>. Furthermore, the short-term stability, evaluated over continuous time intervals of 35 s, showcases exceptional performance. Additionally, the residual drift remains well below 30 MHz.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"181 ","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-15DOI: 10.1016/j.optlastec.2024.111933
Yi Zhuang , Tongtong Xie , Xun Cai , Yudong Wang , Jing Zhou , Shiwei Liu , Wenzhao Liu , Sijie Chen , Hua Wang , Hongyan Fu
In this paper, we have proposed and experimentally demonstrated an optical fiber current sensing system based on optical carrier microwave interferometry (OCMI) technology and the virtual Vernier effect. The OCMI pattern in the electric domain is formed by the interference of optical carrier microwave signals reflected by two fiber Bragg gratings (FBGs). One FBG is attached to a giant magnetostrictive material (GMM): Terfenol-D as the sensing element, while the other one serves as the reference element. Current changes will cause axial tensile strain of the sensing FBG on the material and thus the wavelength of the sensing FBG will change, which will lead to a shift of the frequency of resonance dip of the OCMI pattern in the electric domain. By monitoring the frequency shift, the current change can be demodulated. Two FBGs with different distances (∼ 27 cm and ∼ 5 m) are employed in the experiment, which results in different FSRs and thus sensitivities of the proposed system. In the experiment, we obtained current sensitivities of −111.21 MHz/A and −2.65 MHz/A with increasing current when distances between two FBGs are ∼ 27 cm and ∼ 5 m, respectively. To further increase the sensitivity and improve the flexibility of the proposed system, the virtual Vernier effect is incorporated for the sensing system with FBGs’ distance of ∼ 5 m, without requiring an actual reference interferometer. When increasing current, the sensitivities are 19.82 MHz/A and 32.70 MHz/A by utilizing the virtual fundamental Vernier effect (FVE) and the virtual 1st-order harmonic Vernier effect (HVE), respectively. The proposed sensing system offers advantages such as tunable sensitivity, good repeatability and stability, high resolution, simple structure, and so on.
{"title":"Fiber-optic current sensing system by using optical carrier microwave interferometry technology and virtual Vernier effect","authors":"Yi Zhuang , Tongtong Xie , Xun Cai , Yudong Wang , Jing Zhou , Shiwei Liu , Wenzhao Liu , Sijie Chen , Hua Wang , Hongyan Fu","doi":"10.1016/j.optlastec.2024.111933","DOIUrl":"10.1016/j.optlastec.2024.111933","url":null,"abstract":"<div><div>In this paper, we have proposed and experimentally demonstrated an optical fiber current sensing system based on optical carrier microwave interferometry (OCMI) technology and the virtual Vernier effect. The OCMI pattern in the electric domain is formed by the interference of optical carrier microwave signals reflected by two fiber Bragg gratings (FBGs). One FBG is attached to a giant magnetostrictive material (GMM): Terfenol-D as the sensing element, while the other one serves as the reference element. Current changes will cause axial tensile strain of the sensing FBG on the material and thus the wavelength of the sensing FBG will change, which will lead to a shift of the frequency of resonance dip of the OCMI pattern in the electric domain. By monitoring the frequency shift, the current change can be demodulated. Two FBGs with different distances (∼ 27 cm and ∼ 5 m) are employed in the experiment, which results in different FSRs and thus sensitivities of the proposed system. In the experiment, we obtained current sensitivities of −111.21 MHz/A and −2.65 MHz/A with increasing current when distances between two FBGs are ∼ 27 cm and ∼ 5 m, respectively. To further increase the sensitivity and improve the flexibility of the proposed system, the virtual Vernier effect is incorporated for the sensing system with FBGs’ distance of ∼ 5 m, without requiring an actual reference interferometer. When increasing current, the sensitivities are 19.82 MHz/A and 32.70 MHz/A by utilizing the virtual fundamental Vernier effect (FVE) and the virtual 1st-order harmonic Vernier effect (HVE), respectively. The proposed sensing system offers advantages such as tunable sensitivity, good repeatability and stability, high resolution, simple structure, and so on.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"181 ","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, the recovery of multispectral target scene has garnered increasing attentions from researchers, leading to the development of a series of ghost imaging schemes. However, the existing schemes still possess limitations such as requiring a large number of measurements and subpar performance. Therefore, here, we propose a deep-learning driven multispectral ghost imaging (MGI) scheme based on the sine–cosine optimized patterns (SCOP) for high-efficiency MGI. This scheme adopts a modified pattern selection strategy and relies on the powerful feature-extraction and representation-learning capabilities of multi-scale colour mapping (MSCM) network, which promise high-efficiency MGI for the multispectral target scenes. Experimental results show that the proposed MGI scheme can reconstruct complex multispectral target scenes with high quality at an ultra-low sampling rate (SR) of 2 %. In addition, the proposed scheme has excellent anti-noise performance and performs well in low signal-to-noise ratio (SNR) of 10 dB conditions. Overall, it provides a reliable solution for achieving fast high-quality MGI.
{"title":"High-performance multispectral ghost imaging based on the sine–cosine optimized patterns","authors":"Tiancheng Wang, Weiyun Chen, Wangtao Yu, Bingyi Liu, Kai Guo, Zhongyi Guo","doi":"10.1016/j.optlastec.2024.111969","DOIUrl":"10.1016/j.optlastec.2024.111969","url":null,"abstract":"<div><div>In recent years, the recovery of multispectral target scene has garnered increasing attentions from researchers, leading to the development of a series of ghost imaging schemes. However, the existing schemes still possess limitations such as requiring a large number of measurements and subpar performance. Therefore, here, we propose a deep-learning driven multispectral ghost imaging (MGI) scheme based on the sine–cosine optimized patterns (SCOP) for high-efficiency MGI. This scheme adopts a modified pattern selection strategy and relies on the powerful feature-extraction and representation-learning capabilities of multi-scale colour mapping (MSCM) network, which promise high-efficiency MGI for the multispectral target scenes. Experimental results show that the proposed MGI scheme can reconstruct complex multispectral target scenes with high quality at an ultra-low sampling rate (SR) of 2 %. In addition, the proposed scheme has excellent anti-noise performance and performs well in low signal-to-noise ratio (SNR) of 10 dB conditions. Overall, it provides a reliable solution for achieving fast high-quality MGI.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"181 ","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The indicators of respiratory rate (RespRate), heart rate (HR), and arterial pulse waveform (APW) directly reflect human health levels. Therefore, it is crucial to monitor these indicators. This article introduces a parallel waveguide fiber Bragg grating (PWFBG) sensor capable of measuring respiratory rate and either trunk bending or pulse, and estimating HR based on the measured pulse. Traditional measurement methods require separate sensors for each parameter, leading to increased complexity and cost. We used femtosecond (fs) laser to inscribe a coupling waveguide in a single-mode fiber (SMF), and then inscribed two Fiber Bragg Gratings (FBGs) with different center wavelengths in the fiber core and waveguide respectively, to create the PWFBG structure. To reduce demodulation costs, we made the two FBGs corresponding to the sensor into filters. By using the edge filtering method, we achieved intensity demodulation of the sensor. Finally, the PWFBG structure is encapsulated in polydimethylsiloxane (PDMS) and fixed on the human chest or neck to measure respiratory rate and the degree of trunk bending or pulse. Experimental measurements show that the proposed sensor structure is highly sensitive to human respiration and pulse, and can also assess the degree of trunk bending. In tests, volunteers’ heart rates were 84 bpm at rest, 12 bpm after exercise, and 104 bpm after resting, with results comparing favorably with commercial instruments, falling within the ± 1.96 SD range, demonstrating the sensor’s accuracy. Additionally, the core FBG and waveguide FBG have similar temperature responses (17 pm/℃ and 18.1 pm/℃ respectively), allowing the core FBG to compensate for the temperature changes affecting the waveguide FBG. This sensor has significant potential for health monitoring, health management, and biological research, especially in high magnetic field environments like magnetic resonance imaging (MRI).
{"title":"Parallel waveguide fiber Bragg gratings – Used for detecting human respiratory rate, trunk status, and pulse","authors":"JiaHao Guo , JunYing Zhang , LinPeng Dong , YuJun Du , ZiLong Guo , HaiBin Chen , DaRu Chen , Wei Wang","doi":"10.1016/j.optlastec.2024.111960","DOIUrl":"10.1016/j.optlastec.2024.111960","url":null,"abstract":"<div><div>The indicators of respiratory rate (RespRate), heart rate (HR), and arterial pulse waveform (APW) directly reflect human health levels. Therefore, it is crucial to monitor these indicators. This article introduces a parallel waveguide fiber Bragg grating (PWFBG) sensor capable of measuring respiratory rate and either trunk bending or pulse, and estimating HR based on the measured pulse. Traditional measurement methods require separate sensors for each parameter, leading to increased complexity and cost. We used femtosecond (fs) laser to inscribe a coupling waveguide in a single-mode fiber (SMF), and then inscribed two Fiber Bragg Gratings (FBGs) with different center wavelengths in the fiber core and waveguide respectively, to create the PWFBG structure. To reduce demodulation costs, we made the two FBGs corresponding to the sensor into filters. By using the edge filtering method, we achieved intensity demodulation of the sensor. Finally, the PWFBG structure is encapsulated in polydimethylsiloxane (PDMS) and fixed on the human chest or neck to measure respiratory rate and the degree of trunk bending or pulse. Experimental measurements show that the proposed sensor structure is highly sensitive to human respiration and pulse, and can also assess the degree of trunk bending. In tests, volunteers’ heart rates were 84 bpm at rest, 12 bpm after exercise, and 104 bpm after resting, with results comparing favorably with commercial instruments, falling within the ± 1.96 SD range, demonstrating the sensor’s accuracy. Additionally, the core FBG and waveguide FBG have similar temperature responses (17 pm/℃ and 18.1 pm/℃ respectively), allowing the core FBG to compensate for the temperature changes affecting the waveguide FBG. This sensor has significant potential for health monitoring, health management, and biological research, especially in high magnetic field environments like magnetic resonance imaging (MRI).</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"181 ","pages":"Article 111960"},"PeriodicalIF":4.6,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-14DOI: 10.1016/j.optlastec.2024.111965
Bo Xiao, Guojun Zhao, Shuaihao Ji, Xuexian Lin, Ruisong Zhang, Zhongyu Wang, Yuchen Xue, Huiying Xu, Zhiping Cai
In recent years, the Pr ion has gained great interest due to its vast spectral resources in the visible range. High slope and output power have been the focus of laser development in Pr-doped fibers. In this study, we investigated three different lengths of single-mode Pr:ZBLAN fiber with transitions of 3P0→3H6 and 3F2. The maximum output power of 204 mW and 555 mW were obtained with an optimum length of 23.5 cm and slope efficiencies as high as 65.4 % and 66.28 % at 603 nm and 635 nm, respectively. To the best of our knowledge, these are the maximum output power and slope efficiency at 603 nm and 635 nm in single-mode Pr:ZBLAN fiber pumped by blue laser. These results indicate the potential of single-clad Pr:ZBLAN fiber for visible laser operation with high output performances.
{"title":"High-output performances lasers at 603 nm and 635 nm in Pr:ZBLAN fiber","authors":"Bo Xiao, Guojun Zhao, Shuaihao Ji, Xuexian Lin, Ruisong Zhang, Zhongyu Wang, Yuchen Xue, Huiying Xu, Zhiping Cai","doi":"10.1016/j.optlastec.2024.111965","DOIUrl":"10.1016/j.optlastec.2024.111965","url":null,"abstract":"<div><div>In recent years, the Pr ion has gained great interest due to its vast spectral resources in the visible range. High slope and output power have been the focus of laser development in Pr-doped fibers. In this study, we investigated three different lengths of single-mode Pr:ZBLAN fiber with transitions of <sup>3</sup>P<sub>0</sub>→<sup>3</sup>H<sub>6</sub> and <sup>3</sup>F<sub>2</sub>. The maximum output power of 204 mW and 555 mW were obtained with an optimum length of 23.5 cm and slope efficiencies as high as 65.4 % and 66.28 % at 603 nm and 635 nm, respectively. To the best of our knowledge, these are the maximum output power and slope efficiency at 603 nm and 635 nm in single-mode Pr:ZBLAN fiber pumped by blue laser. These results indicate the potential of single-clad Pr:ZBLAN fiber for visible laser operation with high output performances.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"181 ","pages":"Article 111965"},"PeriodicalIF":4.6,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-14DOI: 10.1016/j.optlastec.2024.111941
Jiangwei Li, Liwen Peng, Song-Sui Li, Liyue Zhang, Xing Ding, Lin Jiang, Xihua Zou, Wei Pan, Lianshan Yan
A vertical-cavity surface-emitting laser (VCSEL) under polarization selected and rotated optical feedback has been proposed and numerically investigated to generate neuron-like spiking dynamics and to show the potential functionalities in spiking information processing. The proposed optical-feedback VCSEL-neuron employs only one laser to simulate one neuron, while conventional optical-injection VCSEL-neurons often require multiple lasers. The input stimulus is conducted by modulating the feedback strength while the output response is monitored by measuring the intensity in the initially non-lasing polarization. On the one hand, the generation of tonic spiking in the form of periodic pulses is related to the frequency difference between the laser’s two orthogonal polarization modes. On the other hand, the generation of phasic spiking in the form of a single abrupt pulse is attributed to the transient response at the onset of self-injection locking. Systematically investigations reveal that the frequency of tonic spiking is roughly proportional to the stimulus strength of input, while the critical stimulus strength of phasic spiking is roughly proportional to the birefringence rate of laser. The potential functionalities of proposed VCSEL-neuron are further verified by single neuron information processing tasks.
{"title":"Photonic spiking neuron based on a single VCSEL with optical feedback","authors":"Jiangwei Li, Liwen Peng, Song-Sui Li, Liyue Zhang, Xing Ding, Lin Jiang, Xihua Zou, Wei Pan, Lianshan Yan","doi":"10.1016/j.optlastec.2024.111941","DOIUrl":"10.1016/j.optlastec.2024.111941","url":null,"abstract":"<div><div>A vertical-cavity surface-emitting laser (VCSEL) under polarization selected and rotated optical feedback has been proposed and numerically investigated to generate neuron-like spiking dynamics and to show the potential functionalities in spiking information processing. The proposed optical-feedback VCSEL-neuron employs only one laser to simulate one neuron, while conventional optical-injection VCSEL-neurons often require multiple lasers. The input stimulus is conducted by modulating the feedback strength while the output response is monitored by measuring the intensity in the initially non-lasing polarization. On the one hand, the generation of tonic spiking in the form of periodic pulses is related to the frequency difference between the laser’s two orthogonal polarization modes. On the other hand, the generation of phasic spiking in the form of a single abrupt pulse is attributed to the transient response at the onset of self-injection locking. Systematically investigations reveal that the frequency of tonic spiking is roughly proportional to the stimulus strength of input, while the critical stimulus strength of phasic spiking is roughly proportional to the birefringence rate of laser. The potential functionalities of proposed VCSEL-neuron are further verified by single neuron information processing tasks.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"181 ","pages":"Article 111941"},"PeriodicalIF":4.6,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-13DOI: 10.1016/j.optlastec.2024.111949
Zhuoer Huang , Yonggang Zou , Xiyao Fu , Xiaohui Ma , Jie Fan , Linlin Shi , Yuxin Yue , Jie Qiu , Xiaozhuo Wang , Biyao Cheng
Dual-wavelength lasers are utilized in dual-wavelength interferometric absorption measurement, difference frequency terahertz generation, and shifted excitation Raman difference spectroscopy. Consequently, dual-wavelength lasers with narrow linewidths and stable wavelengths have become a focal point of research. This paper presents the design of a monolithically integrated dual-wavelength composite grating laser, which integrates laterally coupled gratings and ridge surface gratings with different periods. To reduce mode competition and enhance stability, we designed an isolation groove structure between the two Bragg systems of the laser to achieve selection of two longitudinal modes. At an operating current of 0.28A, two wavelengths with a separation of 0.75 nm were obtained, with central wavelengths of 782.47 nm and 783.22 nm, respectively. When the operating current was in the range of 0.28A to 0.35A, the laser achieved stable dual-wavelength oscillation, with a maximum dual-wavelength output power of 71.95 mW. Thus, the dual-wavelength devices developed in this work can be applied to shifted excitation Raman difference spectroscopy.
{"title":"Dual-wavelength composite grating semiconductor laser for Raman detection","authors":"Zhuoer Huang , Yonggang Zou , Xiyao Fu , Xiaohui Ma , Jie Fan , Linlin Shi , Yuxin Yue , Jie Qiu , Xiaozhuo Wang , Biyao Cheng","doi":"10.1016/j.optlastec.2024.111949","DOIUrl":"10.1016/j.optlastec.2024.111949","url":null,"abstract":"<div><div>Dual-wavelength lasers are utilized in dual-wavelength interferometric absorption measurement, difference frequency terahertz generation, and shifted excitation Raman difference spectroscopy. Consequently, dual-wavelength lasers with narrow linewidths and stable wavelengths have become a focal point of research. This paper presents the design of a monolithically integrated dual-wavelength composite grating laser, which integrates laterally coupled gratings and ridge surface gratings with different periods. To reduce mode competition and enhance stability, we designed an isolation groove structure between the two Bragg systems of the laser to achieve selection of two longitudinal modes. At an operating current of 0.28A, two wavelengths with a separation of 0.75 nm were obtained, with central wavelengths of 782.47 nm and 783.22 nm, respectively. When the operating current was in the range of 0.28A to 0.35A, the laser achieved stable dual-wavelength oscillation, with a maximum dual-wavelength output power of 71.95 mW. Thus, the dual-wavelength devices developed in this work can be applied to shifted excitation Raman difference spectroscopy.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"181 ","pages":"Article 111949"},"PeriodicalIF":4.6,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A 2.1 μm Ho:YAG laser directly pumped by an 888 nm laser diode was demonstrated for the first time, to the best of our knowledge. The output performances of continuous wave and passively Q-switched Ho:YAG laser were investigated at the different output coupler transmittances. For the continuous wave operation, the maximum output power of 396 mW was obtained at the absorbed pump power of 3.7 W, corresponding to the slope efficiency of 22.6 %. For the passively Q-switching operation, the maximum average output power was 103.2 mW at the absorbed pump power of 3.7 W, with a pulse width of 62.9 ns and a repetition frequency of 1.105 kHz. The experiment results show that the 888 nm laser diode is a promising pump source to achieve 2.1 μm laser output in Ho:YAG crystal.
{"title":"888 nm laser diode end-pumped continuous wave and passively Q-switched Ho:YAG laser","authors":"Xiaofan Jing, Xinlu Zhang, Panqiang Kang, Changchang Shen, Jinjer Huang","doi":"10.1016/j.optlastec.2024.111893","DOIUrl":"10.1016/j.optlastec.2024.111893","url":null,"abstract":"<div><div>A 2.1 μm Ho:YAG laser directly pumped by an 888 nm laser diode was demonstrated for the first time, to the best of our knowledge. The output performances of continuous wave and passively Q-switched Ho:YAG laser were investigated at the different output coupler transmittances. For the continuous wave operation, the maximum output power of 396 mW was obtained at the absorbed pump power of 3.7 W, corresponding to the slope efficiency of 22.6 %. For the passively Q-switching operation, the maximum average output power was 103.2 mW at the absorbed pump power of 3.7 W, with a pulse width of 62.9 ns and a repetition frequency of 1.105 kHz. The experiment results show that the 888 nm laser diode is a promising pump source to achieve 2.1 μm laser output in Ho:YAG crystal.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"181 ","pages":"Article 111893"},"PeriodicalIF":4.6,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-12DOI: 10.1016/j.optlastec.2024.111898
Ye Zhang, Xiufang Cui, Xin Wen, Junyan Wang, Xiaotian Fan, Mengran Zha, Xinyu Yi, Guo Jin
Underwater wet laser cladding (UWLC) technology has considerable application potential for in situ repair of offshore engineering equipment. Moreover, multipass UWLC has notable practical application value and can ensure the efficiency of underwater repair processing. A multipass laser cladding layer with high forming quality that is formed in a complex underwater environment has notable application value. Herein, new results regarding the preparation of in situ multipass UWLC duplex stainless steel (DSS) coatings are reported. Multipass ER2209 UWLC coatings are successfully prepared in a completely wet environment. Laser-induced self-protection materials are used to counter and eliminate the effects of the water environment on the forming quality of the UWLC coatings. The results show that the numerous porosity defects on the cladding layer surface are attributed to effects such as laser-induced cavitation and water ionization. Effective use of laser-induced protective materials mitigates the detrimental effects of water intrusion. The rapid cooling effect of the underwater environment is counteracted by the heat input form the underwater multipass laser and the exothermic action of the protective material. Compared with ER2209 air laser cladding (ALC) coatings, the accumulation of dislocations at grain boundary slightly decreases the corrosion resistance of the ER2209 UWLC coatings. Multipass underwater cladding formation assisted by laser-induced protection materials offers valuable theoretical insights for in situ repair of underwater equipment.
{"title":"Exploring laser-induced protection material assisted elevating the forming quality of multi-pass ER2209 coating via underwater wet laser cladding","authors":"Ye Zhang, Xiufang Cui, Xin Wen, Junyan Wang, Xiaotian Fan, Mengran Zha, Xinyu Yi, Guo Jin","doi":"10.1016/j.optlastec.2024.111898","DOIUrl":"10.1016/j.optlastec.2024.111898","url":null,"abstract":"<div><div>Underwater wet laser cladding (UWLC) technology has considerable application potential for in situ repair of offshore engineering equipment. Moreover, multipass UWLC has notable practical application value and can ensure the efficiency of underwater repair processing. A multipass laser cladding layer with high forming quality that is formed in a complex underwater environment has notable application value. Herein, new results regarding the preparation of in situ multipass UWLC duplex stainless steel (DSS) coatings are reported. Multipass ER2209 UWLC coatings are successfully prepared in a completely wet environment. Laser-induced self-protection materials are used to counter and eliminate the effects of the water environment on the forming quality of the UWLC coatings. The results show that the numerous porosity defects on the cladding layer surface are attributed to effects such as laser-induced cavitation and water ionization. Effective use of laser-induced protective materials mitigates the detrimental effects of water intrusion. The rapid cooling effect of the underwater environment is counteracted by the heat input form the underwater multipass laser and the exothermic action of the protective material. Compared with ER2209 air laser cladding (ALC) coatings, the accumulation of dislocations at grain boundary slightly decreases the corrosion resistance of the ER2209 UWLC coatings. Multipass underwater cladding formation assisted by laser-induced protection materials offers valuable theoretical insights for in situ repair of underwater equipment.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"181 ","pages":"Article 111898"},"PeriodicalIF":4.6,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-12DOI: 10.1016/j.optlastec.2024.111945
Yang Gao , Liqing Zhang , Shuang Liu , Rui Li , Tingting Ma , Lei Zhou , Rong Qiu
Potassium dihydrogen phosphate (KH2PO4, KDP) crystals are vital optical materials in Inertial Confinement Fusion (ICF) engineering. Optical properties of KDP crystals induced by nanosecond laser with two wavelengths at different energy densities were investigated by means of ultraviolet–visible (UV–Vis) transmission spectra, infrared (IR) transmission spectra and Raman scattering spectra. Results from UV–Vis spectra showed that transmittance of KDP crystals increased, accompanied by a general reduction in refractivity index, extinction coefficients and photoconductivities after irradiation. Infrared spectra revealed that the KDP crystal successively underwent a breakage of hydrogen bonds, dehydration and formations of new phosphates, as well as recombination of broken segments with an increase in laser energy densities. Raman spectra analysis primarily exhibited that vibration modes of PO43− and H2PO4− groups became disorder, and a new vibration mode, related to PO bonds appeared with respect to energy densities after irradiation with two-wavelength laser. Furthermore, the results from three analysis techniques consistently suggests that KDP crystals were damaged firstly, then repaired, and finally damaged again, with an increase of energy density. And 355 nm laser induced more serious damages than that of 1064 nm laser at the same energy density. Similar damage processes were found after two-wavelength laser irradiation. Moreover, underlying degradation mechanisms in optical properties of KDP crystals were discussed in detail. This work provided insights into the full use of KDP crystal in ICF engineering.
{"title":"Degradation mechanisms of optical properties of KDP crystals induced by nanosecond laser","authors":"Yang Gao , Liqing Zhang , Shuang Liu , Rui Li , Tingting Ma , Lei Zhou , Rong Qiu","doi":"10.1016/j.optlastec.2024.111945","DOIUrl":"10.1016/j.optlastec.2024.111945","url":null,"abstract":"<div><div>Potassium dihydrogen phosphate (KH<sub>2</sub>PO<sub>4</sub>, KDP) crystals are vital optical materials in Inertial Confinement Fusion (ICF) engineering. Optical properties of KDP crystals induced by nanosecond laser with two wavelengths at different energy densities were investigated by means of ultraviolet–visible (UV–Vis) transmission spectra, infrared (IR) transmission spectra and Raman scattering spectra. Results from UV–Vis spectra showed that transmittance of KDP crystals increased, accompanied by a general reduction in refractivity index, extinction coefficients and photoconductivities after irradiation. Infrared spectra revealed that the KDP crystal successively underwent a breakage of hydrogen bonds, dehydration and formations of new phosphates, as well as recombination of broken segments with an increase in laser energy densities. Raman spectra analysis primarily exhibited that vibration modes of PO<sub>4</sub><sup>3−</sup> and H<sub>2</sub>PO<sub>4</sub><sup>−</sup> groups became disorder, and a new vibration mode, related to P<img>O bonds appeared with respect to energy densities after irradiation with two-wavelength laser. Furthermore, the results from three analysis techniques consistently suggests that KDP crystals were damaged firstly, then repaired, and finally damaged again, with an increase of energy density. And 355 nm laser induced more serious damages than that of 1064 nm laser at the same energy density. Similar damage processes were found after two-wavelength laser irradiation. Moreover, underlying degradation mechanisms in optical properties of KDP crystals were discussed in detail. This work provided insights into the full use of KDP crystal in ICF engineering.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"181 ","pages":"Article 111945"},"PeriodicalIF":4.6,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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