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Focus control of wide-angle metalens based on digitally encoded metasurface

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Opto-Electronic Advances 2024年第8期7卷 26-41页

作者： Yi Chen Simeng Zhang Ying Tian Chenxia Li Wenlong Huang Yixin Liu Yongxing Jin Bo Fang Zhi Hong Xufeng Jing Institute of Optoelectronic Technology China Jiliang UniversityHangzhou 310018China Centre for THz Research China Jiliang UniversityHangzhou 310018China college of metrology&measurement engineering China Jiliang UniversityHangzhou 310018China college of Information engineering China Jiliang UniversityHangzhou 310018China

Based on the principle of super-symmetric lens with quadratic phase gradient transformation,combined with the princi-ple of digital coding of metasurface,we propose a wide-angle coded metalens for focusing control in two-dimensional *** metalens achieves focus shift in the x-direction by changing the oblique incidence angle of the incident wave,and focus control in the y-direction by combining with the convolution principle of the digitally coded metasurface to achieve flexible control of light focusing in the two-dimensional *** metasurface unit is mainly composed of three-layer of metal structure and two layers of medium,and the transmission phase is obtained by changing the middle layer of metal structure,which in turn obtains the required phase distribution of the *** design of the metalens real-izes the function of the lens with a large viewing angle at the x-polarized incidence,and realizes two-dimensional focus ***,we prepared the designed coding metalens and tested the focus control function of the wide-an-gle coding *** experimental results are in good agreement with the design results.

关键词： metasurface metalens wide-angle coding

Extending microwave-frequency electric-field detection through single transmission peak method

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Chinese Physics B 2024年第5期33卷 417-423页

作者：刘青陈进湛王赫张杰阮伟民伍国柱郑顺元罗景庭宋振飞 college of Physics and Optoelectronic engineering Shenzhen UniversityShenzhen 518060China Shenzhen Institute for Technology Innovation National Institute of MetrologyShenzhen 518107China Center for Advanced measurement Science National Institute of MetrologyBeijing 100029China

The strength of microwave(MW)electric field can be observed with high precision by using the standard electromagnetically induced transparency and Aulter–Towns(EIT-AT)technique,when its frequency is resonant or nearly-resonant with the Rydberg transition *** the detuning of MW field increases,one of the transmission peaks(single peak)is easier to measure due to its increased *** can be found that the central symmetry point of the two transmission peaks f_(1/2)is only related to the detuning of MW field△_(MW)and central symmetry point f_(0)of resonant MW field,satisfying the relation f_(1/2)=△_(MW)/2+f_(0).Thus,we demonstrate a single transmission peak method that the MW E-field can be determined by interval between the position of single peak and f_(1/2).We use this method to measure continuous frequencies in a band from-200 MHz to 200 MHz of the MW *** experimental results and theoretical analysis are presented to describe the effectiveness of this *** 50 MHz<△_(MW)<200 MHz,this method solves the problem that the AT splitting cannot be measured by using the standard EIT-AT techniques or multiple atomic-level Rydberg atom schemes.

关键词： microwave electric field Rydberg atom electromagnetically induced transparency(EIT) Aulter-Towns splitting

Quantum vector DC magnetometry via selective phase accumulation

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Science China(Physics,Mechanics & Astronomy) 2024年第10期Mechanics & Astronomy) .卷 16-26页

作者： Min Zhuang Sijie Chen Jiahao Huang Chaohong Lee Institute of Quantum Precision measurement State Key Laboratory of Radio Frequency Heterogeneous IntegrationCollege of Physics and Optoelectronic EngineeringShenzhen University Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong) Laboratory of Quantum engineering and Quantum metrology School of Physics and AstronomySun Yat-sen University (Zhuhai Campus)

Precision measurement of magnetic fields is a crucial issue in both fundamental scientific research and practical sensing technology. The sensitive detection of a vector magnetic field poses a significant challenge in quantum magnetometry, particularly in estimating a vector DC magnetic field with high precision. Here, we propose a comprehensive protocol for quantum vector DC magnetometry, utilizing selective phase accumulation in both non-entangled and entangled quantum probes. Building upon the principles of Ramsey interferometry, our protocol enables the selective accumulation of phase for a specific magnetic field component by incorporating a meticulously designed pulse sequence. In the individual measurement scheme, we employ three individual quantum interferometries to independently estimate each of the three magnetic field components. Alternatively, in the simultaneous measurement scheme, the application of a pulse sequence along different directions enables the simultaneous estimation of all three magnetic field components using only one quantum interferometry. Notably, by employing an entangled state(such as the Greenberger-Horne-Zeilinger state) as the input state, the measurement precisions of all three components may reach the Heisenberg limit. This study not only establishes a general protocol for measuring vector magnetic fields using quantum probes, but also presents a viable pathway for achieving entanglement-enhanced multi-parameter estimation.

关键词： magnetometry quantum interferometry entanglement-enhanced quantum metrology

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Research on the identification of the production origin of Angelica dahurica using LIBS technology combined with machine learning algorithms

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Optoelectronics Letters 2024年第3期20卷 171-176页

作者： SUN Jiaxing LI Honglian YAO Yuhang YAN Qiongyan DONG Fang college of Quality and Technology Supervising Hebei UniversityBaoding 071000China National and Local Joint engineering Center of Measuring Instruments and metrology Systems Baoding 071000China Key Laboratory of Energy measurement and Safety Detection Technology in Hebei Province Baoding 071000China

The origin of Angelica dahurica medicinal herbs varies, and their pharmacological effects also differ. In order to achieve rapid and accurate identification of the origin of Angelica dahurica medicinal herbs, this study utilizes laser induced breakdown spectroscopy(LIBS) technology combined with machine learning algorithms to identify the original source of Angelica dahurica. Sliced samples of Angelica dahurica were taken from four regions: Hebei, Henan, Zhejiang, and Sichuan. The spectral data from the sliced samples were used as features, and different algorithms including support vector machine(SVM), back propagation(BP) neural network, genetic algorithm-back propagation(GA-BP) neural network, particle swarm optimization-back propagation(PSO-BP) neural network, convolutional neural network(CNN), and CNN-SVM were employed to classify the origin of Angelica dahurica samples.

关键词： neural origin network

Random Raman Fiber Laser as a Liquid Refractive Index Sensor

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Photonic Sensors 2024年第1期14卷 13-22页

作者： Bing HAN Yuxi MA Han WU Yong ZHAO college of Information Science and engineering Northeastern UniversityShenyang 110819China Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and measurement Technology Qinhuangdao 066004China college of Electronics and Information engineering Sichuan UniversityChengdu 610064China

In this paper,a new concept of forward-pumped random Raman fiber laser(RRFL)-based liquid refractive index sensing is proposed for the first *** liquid refractive index sensing,the flat fiber end immersed in the liquid can act as the point reflector for generating random fiber lasing and also as the sensing *** to the high sensitivity of the output power of the RRFL to the reflectivity provided by the point reflector in the ultralow reflectivity regime,the proposed RRFL is capable of achieving liquid refractive index sensing by measuring the random lasing output *** theoretically investigate the effects of the operating pump power and fiber length on the refractive index sensitivity for the proposed *** a proof-of-concept demonstration,we experimentally realize high-sensitivity half-open short-cavity RRFL-based liquid refractive index sensing with the maximum sensitivity and the sensing resolution of-39.88W/RIU and 2.5075×10^(-5) RIU,*** also experimentally verify that the refractive index sensitivity can be enhanced with the shorter fiber length of the *** work extends the application of the random fiber laser as a new platform for highly-sensitive refractive index sensing in chemical,biomedical,and environmental monitoring applications,etc.

关键词： Fiber optic sensors refractive index measurements fiber lasers Rayleigh scattering stimulated Raman scattering

Accurate Quantification of Pure Thiacloprid with Mass Balance and Quantitative H-NMR

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Journal of Analysis and Testing 2024年第1期8卷 1-8页

作者： Mengling Tu Wei Zhang Yunxiao Zhu Wen Ma Xiao Li Shukun Zhou Hongmei Li Xianjiang Li Key Laboratory of Chemical metrology and Applications on Nutrition and Health for State Market Regulation Division of Metrology in ChemistryNational Institute of MetrologyBeijing 100029China State Key Laboratory of Heavy Oil Processing College of Chemical Engineering and EnvironmentChina University of PetroleumBeijing 102249China State Key Laboratory of Natural and Biomimetic Drugs School of Pharmaceutical SciencesPeking UniversityBeijing 100191China

Thiacloprid is the first-generation neonicotinoid insecticide,which is widely used in modern *** materials are essential for sound measurement and traceability of results in chemical *** thiacloprid was comprehensively assessed by two orthonormal methods:mass balance(MB) and quantitative nuclear magnetic resonance spectroscopy(qNMR).From MB,its mass fraction value was 998.4 mg/g with the subtraction of structurally related impurities(99.87%),inorganic impurities(0.006 mg/g),water(0.33 mg/g),and volatile organic solvent(0 mg/g).To guarantee sufficient separation of structurally related purity,peak purity of thiacloprid was evaluated by five points of UV *** the qNMR of hydrogen,its mass fraction value was 995.7 mg/g which was traced to the internal standard(methyl sulfone).Finally,the certified value was assigned to 997 mg/g,together with an expanded uncertainty of 3 mg/g(k=2).This high-purity thiacloprid can be applied to routine monitoring in agriculture and the food fields.

关键词： Mass balance Quantitative nuclear magnetic resonance spectroscopy Reference material Thiacloprid

Performance Study of MIMO-OSTBC Parallel Relay FSO System Based on GFDM

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Chinese Journal of Electronics 2024年第2期33卷 564-572页

作者： Rui ZHOU Yong WANG Yi WANG Key Laboratory of Electromagnetic Wave Information Technology and metrology of Zhejiang Province College of Information Engineering China Jiliang University State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering Hohai University

This paper investigates the performance of a new generalized frequency division multiplexing(GFDM)parallel relay free space optical(FSO) communication system using multi-input multi-output(MIMO) orthogonal space-time block codes(OSTBC) scheme. Under the M distribution atmospheric turbulence, taking into account the triple effects of irradiance, pointing errors and path loss, the mathematical expression of system symbol error rate is derived with the help of Meijer G-function. The symbol error performance of GFDM is compared with on-off keying,Gaussian minimum shift keying, polarization shift keying and orthogonal frequency division multiplexing(OFDM)modulation methods. The effects of the MIMO-OSTBC parallel relay scheme on the GFDM system including filter roll down coefficient, the number of transmitting and receiving antennas, the number of relays, normalized beamwidth and jitter variance are analyzed, and the numerical results are verified by Monte Carlo simulation. This work provides a good foundation for engineering applications.

关键词： Monte Carlo methods Transmitting antennas Symbols Receiving antennas Modulation Jitter Transceivers

Reconstructing coherent dynamics of bound states induced by strong attosecond XUV pulses

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Chinese Optics Letters 2024年第2期22卷 56-63页

作者：贾利娟刘明清王新强徐龙闫培光姜维超傅立斌 Institute of Quantum Precision measurement College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China Department of Physics Xiamen UniversityXiamen 361005China Graduate School of China Academy of engineering Physics Beijing 100193China

We propose a scheme that utilizes weak-field-induced quantum beats to investigate the electronic coherences of atoms driven by a strong attosecond extreme ultraviolet(XUV)*** technique involves using a strong XUV pump pulse to excite and ionize atoms and a time-delayed weak short pulse to probe the photoelectron *** theoretical analysis demonstrates that the information regarding the bound states,initiated by the strong pump pulse,can be precisely reconstructed from the weak-field-induced quantum beat *** examine this scheme,we apply it to the attosecond XUV laser-induced ionization of hydrogen atoms by solving a three-dimensional time-dependent Schr?dinger *** work provides an essential reference for reconstructing the ultrafast dynamics of bound states induced by strong XUV attosecond pulses.

关键词： attosecond pulse bound-state dynamics quantum beats

Reversible generation of dissipative Kerr solitons in a microresonator by the backward tuning method

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Chinese Optics Letters 2024年第7期22卷 53-58页

作者： Jihui Zheng Lingman Ni Wanghang Gu Linhua Jia Yurun Zhai Qiong Niu Fumin Zhang Xinghua Qu Advanced Photonic Technology Laboratory College of Electronic and Optical Engineering&College of MicroelectronicsNanjing University of Posts and TelecommunicationsNanjing 210023China State Key Laboratory of Precision measurement Technology and Instruments Tianjin UniversityTianjin 300072China

Soliton generation schemes have attracted considerable scholarly *** paper introduces a novel backward tuning method for the reversible generation of dissipative Kerr solitons(DKSs).Reversible soliton generation relies on the thermal stabilization of the auxiliary laser,coupled with backward tuning of the pump laser,significantly increasing the range of soliton steps by over 10 ***,the method alleviates the stringent auxiliary laser detuning *** adjusting the detuning of the auxiliary laser,diverse numbers of solitons can be deterministically generated,enhancing both flexibility and precision.

关键词： microresonator dissipative Kerr soliton reversible generation backward tuning.