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/col202321.112601
Peihua Jie, Zhenwei Xie, Xiaocong Yuan
A new type of power-exponent-phase vortex-like beams with both quadratic and cubic azimuthal phase gradients is investigated in this work. The intensity and orbital angular momentum (OAM) density distributions are noticeably different when the phase gradient increases or decreases along the azimuth angle, while the orthogonality and total OAM remain constant. The characteristics of the optical field undergo a significant change when the phase shifts from linear to nonlinear, with the variation of the power index having little impact on the beam characteristics under nonlinear phase conditions. These characteristics provide new ideas for applications such as particle manipulation, optical communications, and OAM encryption.
{"title":"Optical spiral vortex from azimuthally increasing/decreasing exponential phase gradients","authors":"Peihua Jie, Zhenwei Xie, Xiaocong Yuan","doi":"10.3788/col202321.112601","DOIUrl":"https://doi.org/10.3788/col202321.112601","url":null,"abstract":"A new type of power-exponent-phase vortex-like beams with both quadratic and cubic azimuthal phase gradients is investigated in this work. The intensity and orbital angular momentum (OAM) density distributions are noticeably different when the phase gradient increases or decreases along the azimuth angle, while the orthogonality and total OAM remain constant. The characteristics of the optical field undergo a significant change when the phase shifts from linear to nonlinear, with the variation of the power index having little impact on the beam characteristics under nonlinear phase conditions. These characteristics provide new ideas for applications such as particle manipulation, optical communications, and OAM encryption.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135612370","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/col202321.111201
An Ye, Dingyuan Fu, Mingming Wu, Jiahao Guo, Tianze Sheng, Xiaolin Li, Shangqing Gong, Yueping Niu
Nitrogen-vacancy (NV) centers in diamond are progressively favored for room-temperature magnetic field measurement. The signal to noise ratio (SNR) optimization for NV diamond magnetometry generally concentrates on signal amplitude enhancement rather than efficient noise processing. Here, we report a compound filter system combining a wavelet denoising method and an adaptive filter for the realization of an efficient weak magnetic measurement with a high SNR. It allows enhanced magnetic field measurement with an average SNR enhancement of 17.80 dB at 50 nT within 500 mHz to 100 Hz and 14.76 dB at 500 mHz within 50 nT to 1100 nT. The introduction of this system in NV diamond magnetometry is aimed to improve signal quality by effectively eliminating the noise and retaining ideal signals.
{"title":"SNR enhancement of magnetic fields measurement with the diamond NV center using a compound filter system","authors":"An Ye, Dingyuan Fu, Mingming Wu, Jiahao Guo, Tianze Sheng, Xiaolin Li, Shangqing Gong, Yueping Niu","doi":"10.3788/col202321.111201","DOIUrl":"https://doi.org/10.3788/col202321.111201","url":null,"abstract":"Nitrogen-vacancy (NV) centers in diamond are progressively favored for room-temperature magnetic field measurement. The signal to noise ratio (SNR) optimization for NV diamond magnetometry generally concentrates on signal amplitude enhancement rather than efficient noise processing. Here, we report a compound filter system combining a wavelet denoising method and an adaptive filter for the realization of an efficient weak magnetic measurement with a high SNR. It allows enhanced magnetic field measurement with an average SNR enhancement of 17.80 dB at 50 nT within 500 mHz to 100 Hz and 14.76 dB at 500 mHz within 50 nT to 1100 nT. The introduction of this system in NV diamond magnetometry is aimed to improve signal quality by effectively eliminating the noise and retaining ideal signals.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135612372","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 distribution of metal nanoparticles on the surface of a surface enhancement Raman scattering (SERS)-active substrate plays a prominent part in not only the enhancement of Raman vibration signal, but also the spectrum uniformity. Here, a facile method to fabricate SERS substrates with excellent homogeneity and low cost was proposed, in which a lyotropic liquid crystal soft template was introduced for the coordinated growth of the silver nanoflowers in the process of electrochemistry deposition. Simulation was carried out to illustrate the dominated influence of the distance of electrodes on the deposited nanoparticle number. Two kinds of conductive materials, silver plate and indium tin oxide (ITO) glass, were chosen as the anode, while the cathode was fixed as ITO glass. The simulated conjecture on the effect of electrode flatness on the uniformity of deposited nanoparticles in silver is experimentally proved. More importantly, it was demonstrated that with a relatively smooth and flat ITO glass anode, a SERS substrate featuring higher spectrum uniformity could be achieved. This work is of great significance to the actual applications of the SERS substrate for quantitative detection with high sensitivity.
{"title":"Improvement of Raman spectrum uniformity of SERS substrate based on flat electrode","authors":"Zhihui Jiang, Shen Zhang, Congxi Song, Hongmin Mao, Xin Zhao, Huanjun Lu, Zhaoliang Cao","doi":"10.3788/col202321.113001","DOIUrl":"https://doi.org/10.3788/col202321.113001","url":null,"abstract":"The distribution of metal nanoparticles on the surface of a surface enhancement Raman scattering (SERS)-active substrate plays a prominent part in not only the enhancement of Raman vibration signal, but also the spectrum uniformity. Here, a facile method to fabricate SERS substrates with excellent homogeneity and low cost was proposed, in which a lyotropic liquid crystal soft template was introduced for the coordinated growth of the silver nanoflowers in the process of electrochemistry deposition. Simulation was carried out to illustrate the dominated influence of the distance of electrodes on the deposited nanoparticle number. Two kinds of conductive materials, silver plate and indium tin oxide (ITO) glass, were chosen as the anode, while the cathode was fixed as ITO glass. The simulated conjecture on the effect of electrode flatness on the uniformity of deposited nanoparticles in silver is experimentally proved. More importantly, it was demonstrated that with a relatively smooth and flat ITO glass anode, a SERS substrate featuring higher spectrum uniformity could be achieved. This work is of great significance to the actual applications of the SERS substrate for quantitative detection with high sensitivity.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135612381","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 nonlinear physics dynamics of temporal dissipative solitons in a microcavity hinder them from attaining high power from pump lasers with a typical nonlinear energy conversion efficiency of less than 1%. Here, we experimentally demonstrate a straightforward method for improving the output power of soliton combs using a silica microrod cavity with high coupling strength, large mode volume, and high-Q factor, resulting in a low-repetition-rate dissipative soliton ( ∼ 21 GHz) with an energy conversion efficiency exceeding 20%. Furthermore, by generating an ∼ 105 GHz 5 × FSR (free spectral range) soliton crystal comb in the microcavity, the energy conversion efficiency can be further increased up to 56%.
{"title":"High energy efficiency soliton microcomb generation in high coupling strength, large mode volume, and ultra-high-Q micro-cavity","authors":"Wenwen Cui, Zheng Yi, Xinyu Ma, Yong Geng, Heng Zhou, Kun Qiu","doi":"10.3788/col202321.101902","DOIUrl":"https://doi.org/10.3788/col202321.101902","url":null,"abstract":"The nonlinear physics dynamics of temporal dissipative solitons in a microcavity hinder them from attaining high power from pump lasers with a typical nonlinear energy conversion efficiency of less than 1%. Here, we experimentally demonstrate a straightforward method for improving the output power of soliton combs using a silica microrod cavity with high coupling strength, large mode volume, and high-Q factor, resulting in a low-repetition-rate dissipative soliton ( ∼ 21 GHz) with an energy conversion efficiency exceeding 20%. Furthermore, by generating an ∼ 105 GHz 5 × FSR (free spectral range) soliton crystal comb in the microcavity, the energy conversion efficiency can be further increased up to 56%.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136206802","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/col202321.071202
Qiyu Wang, Zehao Wang, Xiang-Dong Chen, Fangwen Sun
Modulation of a vector light field has played an important role in the research of nanophotonics. However, it is still a great challenge to accurately measure the three-dimensional vector distribution at nanoscale. Here, based on the interaction between the light field and atomic-sized nitrogen-vacancy (NV) color center in diamonds, we demonstrate an efficient method for vectorial mapping of the light-field distribution at nanoscale. Single NV centers with different but well-defined symmetry axes are selected and then interact with the same tightly focused light field. The excitation of a single NV center is related to the angle between the NV center axis and the polarization of the light field. Then the fluorescence patterns of different NV centers provide the information on the vectorial light field distribution. Subsequently analyzing the fluorescence patterns with the help of a deep neural network, the intensity and phase of the light-field vectorial components are fully reconstructed with nanometer resolution. The experimental results are in agreement with theoretical calculations. It demonstrates that our method can help to study light – matter interaction at nanoscale and extend the application of vector light fields in research on nanophotonics.
{"title":"Detecting the vector of nanoscale light field with atomic defect","authors":"Qiyu Wang, Zehao Wang, Xiang-Dong Chen, Fangwen Sun","doi":"10.3788/col202321.071202","DOIUrl":"https://doi.org/10.3788/col202321.071202","url":null,"abstract":"Modulation of a vector light field has played an important role in the research of nanophotonics. However, it is still a great challenge to accurately measure the three-dimensional vector distribution at nanoscale. Here, based on the interaction between the light field and atomic-sized nitrogen-vacancy (NV) color center in diamonds, we demonstrate an efficient method for vectorial mapping of the light-field distribution at nanoscale. Single NV centers with different but well-defined symmetry axes are selected and then interact with the same tightly focused light field. The excitation of a single NV center is related to the angle between the NV center axis and the polarization of the light field. Then the fluorescence patterns of different NV centers provide the information on the vectorial light field distribution. Subsequently analyzing the fluorescence patterns with the help of a deep neural network, the intensity and phase of the light-field vectorial components are fully reconstructed with nanometer resolution. The experimental results are in agreement with theoretical calculations. It demonstrates that our method can help to study light – matter interaction at nanoscale and extend the application of vector light fields in research on nanophotonics.","PeriodicalId":10293,"journal":{"name":"Chinese Optics Letters","volume":"13 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78812473","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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