Spatial terahertz wave modulators that can arbitrarily tailor the electromagnetic wavefront are in high demand in nondestructive inspections and high-capacity wireless communications. Here, we propose a liquid crystal integrated metadevice. It modulates the terahertz wave based on the adjustable electromagnetically induced transparency analog when spatially changing the environmental refractive index. The functions of the device can be arbitrarily programmed via photo-reorienting the directors of liquid crystals with a digital micromirror device-based exposing system. The thin liquid crystal layer can be further driven by an electric field, and thus the function can be rapidly switched. Amplitude modulation and the lens effect are demonstrated with modulation depths over 50% at 0.94 THz.
{"title":"Photo-reconfigurable and electrically switchable spatial terahertz wave modulator [Invited]","authors":"Hongguan Yu, Huacai Wang, Zhixiong Shen, Shina Tao, Shijun Ge, Wei Hu","doi":"10.3788/col202321.010002","DOIUrl":"https://doi.org/10.3788/col202321.010002","url":null,"abstract":"Spatial terahertz wave modulators that can arbitrarily tailor the electromagnetic wavefront are in high demand in nondestructive inspections and high-capacity wireless communications. Here, we propose a liquid crystal integrated metadevice. It modulates the terahertz wave based on the adjustable electromagnetically induced transparency analog when spatially changing the environmental refractive index. The functions of the device can be arbitrarily programmed via photo-reorienting the directors of liquid crystals with a digital micromirror device-based exposing system. The thin liquid crystal layer can be further driven by an electric field, and thus the function can be rapidly switched. Amplitude modulation and the lens effect are demonstrated with modulation depths over 50% at 0.94 THz.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"155 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83191604","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}
Aoran Feng (丰傲然), Bowen Liu (刘博文), Dongyu Yan (闫东钰), Genyu Bi (毕根毓), Youjian Song (宋有建), and Minglie Hu (胡明列) 1 Ultrafast Laser Laboratory, Key Laboratory of Opto-electronic Information Technology (Ministry of Education), School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072, China 2 Georgia Tech Shenzhen Institute, Tianjin University, Shenzhen 518055, China 3 Optoelectronic Detection and Processing Laboratory, School of Electronic Engineering, Tianjin University of Technology and Education, Tianjin 300222, China
{"title":"Sideband-free dispersion-managed Yb-doped mode-locked fiber laser with Gires–Tournois interferometer mirrors","authors":"Aoran Feng, Bowen Liu, Dongyu Yan, Genyu Bi, Youjian Song, Minglie Hu","doi":"10.3788/col202321.061401","DOIUrl":"https://doi.org/10.3788/col202321.061401","url":null,"abstract":"Aoran Feng (丰傲然), Bowen Liu (刘博文), Dongyu Yan (闫东钰), Genyu Bi (毕根毓), Youjian Song (宋有建), and Minglie Hu (胡明列) 1 Ultrafast Laser Laboratory, Key Laboratory of Opto-electronic Information Technology (Ministry of Education), School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072, China 2 Georgia Tech Shenzhen Institute, Tianjin University, Shenzhen 518055, China 3 Optoelectronic Detection and Processing Laboratory, School of Electronic Engineering, Tianjin University of Technology and Education, Tianjin 300222, China","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"82 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74333578","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/col202321.023001
Xin Peng, Min-sun Chen, Hao Liu
We present a non-contact optical investigation of laser-induced plasma at moderate Ar pressure ranging from 1 to 100 Pa. The significant shock front and spatial fractionation among the different charged ions are demonstrated at the pressure of 20 Pa. The collisions between Si IV ions and ambient Ar atoms generate distinct and excited Ar II ions, fresh Si III ions, and electrons at the dense layer. The electron density peaks at the position of the shock front, indicating that the collision that yields electrons is dominant over the recombination process in the region of the shock layer and its immediate vicinity.
{"title":"Optical emission spectrometric diagnosis of laser-induced plasma and shock front produced at moderate pressure","authors":"Xin Peng, Min-sun Chen, Hao Liu","doi":"10.3788/col202321.023001","DOIUrl":"https://doi.org/10.3788/col202321.023001","url":null,"abstract":"We present a non-contact optical investigation of laser-induced plasma at moderate Ar pressure ranging from 1 to 100 Pa. The significant shock front and spatial fractionation among the different charged ions are demonstrated at the pressure of 20 Pa. The collisions between Si IV ions and ambient Ar atoms generate distinct and excited Ar II ions, fresh Si III ions, and electrons at the dense layer. The electron density peaks at the position of the shock front, indicating that the collision that yields electrons is dominant over the recombination process in the region of the shock layer and its immediate vicinity.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"10 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85966442","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/col202321.100201
Guoqi Bian, Biao Shan, Lianghui Huang, Jing Zhang
We report the measurement of the electromagnetically induced transparency (EIT) with Rydberg states in ultracold 40 K Fermi gases, which is obtained through a two-photon process with the ladder scheme. Rydberg – EIT lines are obtained by measuring the atomic losses instead of the transmitted probe beam. Based on the laser frequency stabilization locking to the superstable cavity, we study the Rydberg – EIT line shapes for the 37s and 35d states. We experimentally demonstrate the significant change in the Rydberg – EIT spectrum by changing the principal quantum number of the Rydberg state (n = 37 = 52 and l = 0). Moreover, the transparency peak position shift is observed, which may be induced by the interaction of the Rydberg atoms. This work provides a platform to explore many interesting behaviors involving Rydberg states in ultracold Fermi gases.
{"title":"Rydberg electromagnetically induced transparency in 40K ultracold Fermi gases","authors":"Guoqi Bian, Biao Shan, Lianghui Huang, Jing Zhang","doi":"10.3788/col202321.100201","DOIUrl":"https://doi.org/10.3788/col202321.100201","url":null,"abstract":"We report the measurement of the electromagnetically induced transparency (EIT) with Rydberg states in ultracold 40 K Fermi gases, which is obtained through a two-photon process with the ladder scheme. Rydberg – EIT lines are obtained by measuring the atomic losses instead of the transmitted probe beam. Based on the laser frequency stabilization locking to the superstable cavity, we study the Rydberg – EIT line shapes for the 37s and 35d states. We experimentally demonstrate the significant change in the Rydberg – EIT spectrum by changing the principal quantum number of the Rydberg state (n = 37 = 52 and l = 0). Moreover, the transparency peak position shift is observed, which may be induced by the interaction of the Rydberg atoms. This work provides a platform to explore many interesting behaviors involving Rydberg states in ultracold Fermi gases.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"30 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79158820","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, an optical pulse amplitude modulation with 4 levels (PAM-4) using a fiber combiner is proposed to enhance the data rate of a field-programmable gate-array-based long-distance real-time underwater wireless optical communication system. Two on – off keying signals with different amplitudes are used to modulate two pigtailed laser diodes, respectively, and the generated optical signals are superimposed into optical PAM-4 signals by a fiber combiner. The optical PAM-4 scheme can effectively alleviate the nonlinearity, although it reduces the peak-to-peak value of the emitting optical power by 25%. A real-time data rate of 187.5 Mbit/s is achieved by using the optical PAM-4 with a transmission distance of 50 m. The data rate is increased by about 25% compared with the conventional electrical PAM-4 in the same condition.
{"title":"50 m/187.5 Mbit/s real-time underwater wireless optical communication based on optical superimposition","authors":"Yongxin Cheng, Xingqi Yang, Yufan Zhang, Chao Zhang, Hao Zhang, Zhijian Tong, Yizhan Dai, Weichao Lü, Xin Li, Haiwu Zou, Zejun Zhang, Jing Xu","doi":"10.3788/col202321.020601","DOIUrl":"https://doi.org/10.3788/col202321.020601","url":null,"abstract":"In this paper, an optical pulse amplitude modulation with 4 levels (PAM-4) using a fiber combiner is proposed to enhance the data rate of a field-programmable gate-array-based long-distance real-time underwater wireless optical communication system. Two on – off keying signals with different amplitudes are used to modulate two pigtailed laser diodes, respectively, and the generated optical signals are superimposed into optical PAM-4 signals by a fiber combiner. The optical PAM-4 scheme can effectively alleviate the nonlinearity, although it reduces the peak-to-peak value of the emitting optical power by 25%. A real-time data rate of 187.5 Mbit/s is achieved by using the optical PAM-4 with a transmission distance of 50 m. The data rate is increased by about 25% compared with the conventional electrical PAM-4 in the same condition.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"19 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73542376","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/col202321.081401
Z. Ye, Xiaolong Zhou, Shushan Jiang, Meng Huang, Fei Wu, Dongge Lei
An immersed liquid cooling slab laser is demonstrated with deionized water as the coolant and a Nd:YAG slab as the gain medium. Using waveguides, a highly uniform pump beam distribution is achieved, and the flow velocity distribution is also optimized in the channels of the gain module (GM). At various flow velocities, the convective heat transfer coefficient (CHTC) is obtained. Experimentally, a maximum output power of 434 W is obtained with an optical – optical efficiency of 27.1% and a slope efficiency of 36.6%. To the best of our knowledge, it is the highest output power of an immersed liquid cooling laser oscillator with a single Nd:YAG slab.
{"title":"Immersed liquid cooling Nd:YAG slab laser oscillator","authors":"Z. Ye, Xiaolong Zhou, Shushan Jiang, Meng Huang, Fei Wu, Dongge Lei","doi":"10.3788/col202321.081401","DOIUrl":"https://doi.org/10.3788/col202321.081401","url":null,"abstract":"An immersed liquid cooling slab laser is demonstrated with deionized water as the coolant and a Nd:YAG slab as the gain medium. Using waveguides, a highly uniform pump beam distribution is achieved, and the flow velocity distribution is also optimized in the channels of the gain module (GM). At various flow velocities, the convective heat transfer coefficient (CHTC) is obtained. Experimentally, a maximum output power of 434 W is obtained with an optical – optical efficiency of 27.1% and a slope efficiency of 36.6%. To the best of our knowledge, it is the highest output power of an immersed liquid cooling laser oscillator with a single Nd:YAG slab.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"14 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87577277","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/col202321.023603
Chenxi Pu, Zhuo Wang, Shulin Sun, Lei Zhou, Qiong He
Metasurfaces have exhibited great capabilities to control electromagnetic waves, and many multifunctional metasurfaces were recently proposed. However, although angle-multiplexed meta-devices were successfully realized in reflection geometries, their transmission-mode counterparts are difficult to achieve due to the additional requirements. Here, we design and fabricate a transmissive angle-multiplexed meta-polarizer in the microwave regime based on a multilayer metasurface. Coupled-mode-theory analyses reveal that the device exhibits distinct angle-dependent transmissive responses under exci-tations with different polarizations, and such differences are further enhanced by multiple scatterings inside the device. Microwave experimental results are in good agreement with numerical simulations and theoretical analyses. dispersions of Fabry – Perot (FP) resonance modes of different polarizations supported by the system. Excellent agreement among microwave experiments, numerical simulations, and theoretical analyses validates our design strategy. Our findings open up a new way to design transmissive angle-multiplexed meta-devices, which may yield many applications in practice.
{"title":"Transmissive angle-multiplexed meta-polarizer based on a multilayer metasurface","authors":"Chenxi Pu, Zhuo Wang, Shulin Sun, Lei Zhou, Qiong He","doi":"10.3788/col202321.023603","DOIUrl":"https://doi.org/10.3788/col202321.023603","url":null,"abstract":"Metasurfaces have exhibited great capabilities to control electromagnetic waves, and many multifunctional metasurfaces were recently proposed. However, although angle-multiplexed meta-devices were successfully realized in reflection geometries, their transmission-mode counterparts are difficult to achieve due to the additional requirements. Here, we design and fabricate a transmissive angle-multiplexed meta-polarizer in the microwave regime based on a multilayer metasurface. Coupled-mode-theory analyses reveal that the device exhibits distinct angle-dependent transmissive responses under exci-tations with different polarizations, and such differences are further enhanced by multiple scatterings inside the device. Microwave experimental results are in good agreement with numerical simulations and theoretical analyses. dispersions of Fabry – Perot (FP) resonance modes of different polarizations supported by the system. Excellent agreement among microwave experiments, numerical simulations, and theoretical analyses validates our design strategy. Our findings open up a new way to design transmissive angle-multiplexed meta-devices, which may yield many applications in practice.","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":"75138049","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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