Pub Date : 2023-01-01DOI: 10.3788/col202321.013601
T. Zhuang, Hai Hu, Q. Zhan
The chiral feature of an optical field can be evaluated by the parameter of g-factor enhancement, which is helpful to enhance chiroptic signals from a chiral dipole. In this work, the superchiral spot has been theoretically proposed in metal-insulator-metal waveguides. The g-factor enhancement of the superchiral spot can be enhanced by 67-fold more than that of circularly polarized light, and the spot is confined in the deep wavelength scale along each spatial dimension. Moreover, the position of the superchiral spot can be tuned by manipulating the incident field. The tunable superchiral spot may find applications in chiral imaging and sensing.
{"title":"Generation of tunable superchiral spot in metal-insulator-metal waveguide","authors":"T. Zhuang, Hai Hu, Q. Zhan","doi":"10.3788/col202321.013601","DOIUrl":"https://doi.org/10.3788/col202321.013601","url":null,"abstract":"The chiral feature of an optical field can be evaluated by the parameter of g-factor enhancement, which is helpful to enhance chiroptic signals from a chiral dipole. In this work, the superchiral spot has been theoretically proposed in metal-insulator-metal waveguides. The g-factor enhancement of the superchiral spot can be enhanced by 67-fold more than that of circularly polarized light, and the spot is confined in the deep wavelength scale along each spatial dimension. Moreover, the position of the superchiral spot can be tuned by manipulating the incident field. The tunable superchiral spot may find applications in chiral imaging and sensing.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"81 1 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80607870","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 : 2023-01-01DOI: 10.3788/col202321.030601
P. Anisimov, E. Tsyplakov, V. Zemlyakov, Jiexing Gao
We propose an alternative approach to compensation of intermodal interactions in few-mode optical fibers by means of digital backpropagation. Instead of solving the inverse generalized multimode nonlinear Schrödinger equation, we accom-plish backpropagation of the multimode signals with help of their near-field intensity distributions captured by a camera. We demonstrate that this task can successfully be handled by a deep neural network and provide a proof of concept by training an autoencoder for backpropagation of six linearly polarized (LP) modes of a step-index fiber.
{"title":"Speckle backpropagation for compensation of nonlinear effects in few-mode optical fibers","authors":"P. Anisimov, E. Tsyplakov, V. Zemlyakov, Jiexing Gao","doi":"10.3788/col202321.030601","DOIUrl":"https://doi.org/10.3788/col202321.030601","url":null,"abstract":"We propose an alternative approach to compensation of intermodal interactions in few-mode optical fibers by means of digital backpropagation. Instead of solving the inverse generalized multimode nonlinear Schrödinger equation, we accom-plish backpropagation of the multimode signals with help of their near-field intensity distributions captured by a camera. We demonstrate that this task can successfully be handled by a deep neural network and provide a proof of concept by training an autoencoder for backpropagation of six linearly polarized (LP) modes of a step-index fiber.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"15 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89372602","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 : 2023-01-01DOI: 10.3788/col202321.043001
Haochen Li, Tianyuan Liu, Yuchao Fu, Wanxiang Li, Meng Zhang, Xi Yang, Di Song, Jiaqi Wang, You Wang, Mei-Ling Huang
{"title":"Rapid classification of copper concentrate by portable laser-induced breakdown spectroscopy combined with transfer learning and deep convolutional neural network","authors":"Haochen Li, Tianyuan Liu, Yuchao Fu, Wanxiang Li, Meng Zhang, Xi Yang, Di Song, Jiaqi Wang, You Wang, Mei-Ling Huang","doi":"10.3788/col202321.043001","DOIUrl":"https://doi.org/10.3788/col202321.043001","url":null,"abstract":"","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"11 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86060899","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 : 2023-01-01DOI: 10.3788/col202321.021401
Jian Feng, C. Tong, Yufei Zhao, A. Popp, B. Schmidt, Li-Jie Wang, B. Meng, Huan-yu Lu, Yanjing Wang, Xin Zhang, Lijun Wang
We report a wavelength-tunable multi-point pump scheme of the semiconductor disk lasers (SDLs). By designing an external cavity of SDL with an intra-cavity transmission grating, multiple pump gain regions share the same resonator. The effect of the intra-cavity grating on the output laser power, wavelength, and beam quality was investigated. The emission wavelength could be tuned over a bandwidth of ∼ 18 nm. With multi-point pumping, we achieve the laser output power with almost no loss, and further improvement is limited by the thermal effect. The changes in the beam are due to the mode selectivity by the intra-cavity grating. DOI:
{"title":"Wavelength-tunable multi-point pump semiconductor disk laser based on an intra-cavity transmission grating","authors":"Jian Feng, C. Tong, Yufei Zhao, A. Popp, B. Schmidt, Li-Jie Wang, B. Meng, Huan-yu Lu, Yanjing Wang, Xin Zhang, Lijun Wang","doi":"10.3788/col202321.021401","DOIUrl":"https://doi.org/10.3788/col202321.021401","url":null,"abstract":"We report a wavelength-tunable multi-point pump scheme of the semiconductor disk lasers (SDLs). By designing an external cavity of SDL with an intra-cavity transmission grating, multiple pump gain regions share the same resonator. The effect of the intra-cavity grating on the output laser power, wavelength, and beam quality was investigated. The emission wavelength could be tuned over a bandwidth of ∼ 18 nm. With multi-point pumping, we achieve the laser output power with almost no loss, and further improvement is limited by the thermal effect. The changes in the beam are due to the mode selectivity by the intra-cavity grating. DOI:","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"2 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82433745","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 : 2023-01-01DOI: 10.3788/col202321.051403
Li Jiang, R. Song, J. Hou
A monolithic visible supercontinuum (SC) source with a record average output power of 204 W and a spectrum ranging from 580 nm to beyond 2400 nm is achieved in a piece of standard telecom graded-index multimode fiber (GRIN MMF) by designing the pumping system. The influence of the GRIN MMF length on the geometrical parameter instability (GPI) effect is analyzed for the first time, to the best of our knowledge, by comparing the SC spectral region dominated by the GPI effect under different fiber lengths. Our work could pave the way for robust, cost-effective, and high-power visible SC sources.
{"title":"Hundred-watt level all-fiber visible supercontinuum generation from a graded-index multimode fiber","authors":"Li Jiang, R. Song, J. Hou","doi":"10.3788/col202321.051403","DOIUrl":"https://doi.org/10.3788/col202321.051403","url":null,"abstract":"A monolithic visible supercontinuum (SC) source with a record average output power of 204 W and a spectrum ranging from 580 nm to beyond 2400 nm is achieved in a piece of standard telecom graded-index multimode fiber (GRIN MMF) by designing the pumping system. The influence of the GRIN MMF length on the geometrical parameter instability (GPI) effect is analyzed for the first time, to the best of our knowledge, by comparing the SC spectral region dominated by the GPI effect under different fiber lengths. Our work could pave the way for robust, cost-effective, and high-power visible SC sources.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"51 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83951435","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 : 2023-01-01DOI: 10.3788/col202321.041604
{"title":"Atomic structures and carrier dynamics of defects in a ZnGeP2 crystal","authors":"","doi":"10.3788/col202321.041604","DOIUrl":"https://doi.org/10.3788/col202321.041604","url":null,"abstract":"","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"4 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79499454","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 this paper, high-uniformity 2 × 64 silicon avalanche photodiode (APD) arrays are reported. Silicon multiple epitaxy technology was used, and the high performance APD arrays based on double-layer epiwafers are achieved for the first time, to the best of our knowledge. A high-uniformity breakdown voltage with a fluctuation of smaller than 3.5 V is obtained for the fabricated APD arrays. The dark currents are below 90 pA for all 128 pixels at unity gain voltage. The pixels in the APD arrays show a gain factor of larger than 300 and a peak responsivity of 0.53 A = W@M= 1 at 850 nm (corresponding to maximum external quantum efficiency of 81%) at room temperature. Quick optical pulse response time was measured, and a corresponding cutoff frequency up to 100 MHz was obtained. dark current.
本文报道了高均匀性2 × 64硅雪崩光电二极管(APD)阵列。据我们所知，采用硅多外延技术，首次实现了基于双层外延片的高性能APD阵列。制备的APD阵列击穿电压波动小于3.5 V，具有较高的均匀性。在单位增益电压下，所有128个像素的暗电流低于90pa。在室温下，APD阵列像素的增益系数大于300，在850 nm处的峰值响应度为0.53 a = W@M= 1(对应于81%的最大外量子效率)。测量了快速的光脉冲响应时间，得到了相应的截止频率高达100mhz。暗电流。
{"title":"High-uniformity 2 × 64 silicon avalanche photodiode arrays with silicon multiple epitaxy technology","authors":"Tiancai Wang, Peng Cao, Hongling Peng, Chuanwang Xu, Hai-Xi Song, Wanhua Zheng","doi":"10.3788/col202321.032501","DOIUrl":"https://doi.org/10.3788/col202321.032501","url":null,"abstract":"In this paper, high-uniformity 2 × 64 silicon avalanche photodiode (APD) arrays are reported. Silicon multiple epitaxy technology was used, and the high performance APD arrays based on double-layer epiwafers are achieved for the first time, to the best of our knowledge. A high-uniformity breakdown voltage with a fluctuation of smaller than 3.5 V is obtained for the fabricated APD arrays. The dark currents are below 90 pA for all 128 pixels at unity gain voltage. The pixels in the APD arrays show a gain factor of larger than 300 and a peak responsivity of 0.53 A = W@M= 1 at 850 nm (corresponding to maximum external quantum efficiency of 81%) at room temperature. Quick optical pulse response time was measured, and a corresponding cutoff frequency up to 100 MHz was obtained. dark current.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"274 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79537870","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 : 2023-01-01DOI: 10.3788/col202321.063801
Xiaomei Dong, Yuhan Du, Miaohua Xu, Yutong Li, Zhe Zhang, Yingjun Li
In the scheme of fast ignition of inertial confinement fusion, the fuel temperature mainly relies on fast electrons, which act as an energy carrier, transferring the laser energy to the fuel. Both conversion efficiency from the laser to the fast electron and the energy spectrum of the fast electron are essentially important to achieve highly effective heating. In this study, a two-dimensional particle in cell simulation is applied to study the generation of fast electrons from solid-density plasmas with different laser waveforms. The results have shown that the slope of the rising edge has a significant effect on fast electron generation and energy absorption. For the negative skew pulse with a relatively slow rising edge, the J × B mechanism can most effectively accelerate the electrons. The overall absorption efficiency of the laser energy is optimized, and the fast electron yield in the middle- and low-energy range is also improved.
{"title":"Effects of laser waveform on the generation of fast electrons in laser–solid interactions","authors":"Xiaomei Dong, Yuhan Du, Miaohua Xu, Yutong Li, Zhe Zhang, Yingjun Li","doi":"10.3788/col202321.063801","DOIUrl":"https://doi.org/10.3788/col202321.063801","url":null,"abstract":"In the scheme of fast ignition of inertial confinement fusion, the fuel temperature mainly relies on fast electrons, which act as an energy carrier, transferring the laser energy to the fuel. Both conversion efficiency from the laser to the fast electron and the energy spectrum of the fast electron are essentially important to achieve highly effective heating. In this study, a two-dimensional particle in cell simulation is applied to study the generation of fast electrons from solid-density plasmas with different laser waveforms. The results have shown that the slope of the rising edge has a significant effect on fast electron generation and energy absorption. For the negative skew pulse with a relatively slow rising edge, the J × B mechanism can most effectively accelerate the electrons. The overall absorption efficiency of the laser energy is optimized, and the fast electron yield in the middle- and low-energy range is also improved.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"61 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78320815","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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