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Dual-color terahertz spatial light modulator for single-pixel imaging

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Light(Science & Applications) 2022年第7期11卷 1585-1594页

作者： Weili Li Xuemei Hu jingbo Wu Kebin Fan Benwen Chen Caihong Zhang Wei Hu Xun Cao Biaobing Jin Yanqing Lu Jian Chen Peiheng Wu Research Institute of Superconductor Electronics(RISE) School of Electronic Science and EngineeringNanjing UniversityNanjing 210023China School of Electronic Science and Engineering Nanjing UniversityNanjing 210023China Purple Mountain Laboratories Nanjing 211111China National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced Microstructures and College of Engineering and Applied SciencesNanjing University163 Xianlin AvenueNanjing 210023China

Spatial light modulators(SLM),capable of dynamically and spatially manipulating electromagnetic waves,have reshaped modern life in projection display and remote sensing.The progress of SLM will expedite next-generation communication and biomedical imaging in the terahertz(THz)range.However,most current THz SLMs are adapted from optical alternatives that still need improvement in terms of uniformity,speed,and bandwidth.Here,we designed,fabricated,and characterized an 8×8THz SLM based on tunable liquid crystal metamaterial absorbers for THz single-pixel compressive imaging.We demonstrated dual-color compressive sensing(CS)imaging for dispersive objects utilizing the large frequency shift controlled by an external electric field.We developed auto-calibrated compressive sensing(ACS)algorithm to mitigate the impact of the spatially nonuniform THz incident beam and pixel modulation,which significantly improves the fidelity of reconstructed images.Furthermore,the complementary modulation at two absorption frequencies enables Hadamard masks with negative element values to be realized by frequency-switching,thereby halving the imaging time.The demonstrated imaging system paves a new route for THz single-pixel multispectral imaging with high reliability and low cost.

关键词： modulator spatially light

Effect of loss and coupling on the resonance of metamaterial:An equivalent circuit approach

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Science China(Information Sciences) 2014年第12期57卷 168-175页

作者： ZHANG YongGang WU jingBo LIANG LanJu ZHOU GaoChao jin biaobing FENG YiJun Research Institute of Superconductor Electronics (RISE) School of Electronic Science and EngineeringNanjing University School of Electrical and Information Engineering Anhui University of Science and Technology Department of Electronic Engineering School of Electronic Science and Engineering Nanjing University

In this work we establish an equivalent circuit model to analyze the resonace of the metamaterial considering the loss of the unit cell and coupling effect between them.From this model,we find that metamaterial can be divided into three categories:weak,critical and strong couplings,depending on the values of the loss and coupling strength,where the different resonant properties are presented.The physical reason of the division is whether the loss in each unit cell can be offset by energy coupling from the adjunct unit cells.Full-wave electromagnetic simulations have also been carried out to verify the equivalent circuit analysis.Our circuit analysis provides a simple and effective way to understand the coupling of the metamaterial and gives guidance for the analysis and design of the metamaterial.

关键词： metamaterials equivalent circuit resonant property coupling frequency splitting

Extraction of material parameters of a bi-layer structure using Terahertz time-domain spectroscopy

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Science China(Information Sciences) 2014年第8期57卷 238-247页

作者： jin biaobing ZHANG CaiHong SHEN XiaoFang MA jinLong CHEN Jian SHI ShengCai WU PeiHeng Research Institute of Superconductor Electronics (RISE) School of Electronic Science and EngineeringNanjing University Purple Mountain Observatory Chinese Academy of Sciences Graduate School of Chinese Academy of Sciences Chinese Academy of Sciences

For a bi-layer structure consisting of a film deposited on a substrate,a new extraction method is proposed using which we can extract both the material parameters of the film and the thickness of the substrate from the measured Terahertz transmission through it,so long as the complex refractive index of the substrate is known beforehand.This method is applicable to a range of refractive indices of the film less than the refractive index of the substrate and a very wide range of layer thicknesses from 20μm to at least 200μm.It is very useful in some cases where the thickness of the substrate cannot be determined using conventional methods such as a Vernier caliper or micrometer screw.

关键词： material parameter Terahertz spectrum extraction method anti-reflection coating layer THztime-domain spectroscopy

A simple Fourier transform spectrometer for terahertz applications

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Chinese Science Bulletin 2012年第6期57卷 573-578页

作者： JIANG Yi LIANG Ming jin biaobing KANG Lin XU WeiWei CHEN Jian WU PeiHeng Research Institute of Superconducting Electronics Nanjing UniversityNanjing 210093China

A simple Fourier transform spectrometer was designed and constructed for the measurement of detectors,sources,passive devices and materials in the terahertz(THz) range.It can be operated at frequencies between 0.3 and 1.5 THz,using a 50-μm-thick Mylar-film beam splitter.The spectral range can be changed by altering the thickness of the beam splitter.The highest frequency resolution is 750 MHz.We studied the properties of heterodyne detectors including superconductor mixers and semiconductor harmonic mixers,direct detectors including an InSb semiconductor bolometer,superconducting tunnel junctions and the Golay cell,and sources including Gunn oscillators and a microwave source with its multipliers,as well as various materials and passive devices including Si wafers and metal mesh filters.

关键词：傅里叶变换光谱仪太赫兹应用无源器件出现频率谐波混频器超导混频器超导隧道结

Temperature dependence of niobium superconducting nanowire single-photon detectors in He-3 cryocooler

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Chinese Science Bulletin 2014年第28期59卷 3549-3553页

作者： Tao Jia Chao Wan Limin Zhao Yu Zhou Qingyuan Zhao Min Gu Xiaoqing Jia Labao Zhang Biaobing Jin Jian Chen Lin Kang Research Institute of Superconductor Electronics (RISE) Nanjing University

Performances of superconducting nanowire single-photon detectors(SNSPDs) based on low TCmaterials strongly depend on the operating temperatures. We have fabricated infrared-sensitive niobium SNSPDs based on doped niobium(Nb*) films and measured them in He-3cryocooler. The critical current approaches to the de-pairing current at 0.3 K. Therefore, with the decrease in temperatures, we have observed a monotonous increase of count rate at the wavelength of 1,521 nm and exponential decrease of dark count rate at all bias currents. The possible origin of dark counts for doped Nb devices is also discussed.

关键词：单光子探测器纳米线制冷机温度依赖性超导铌氦3 临界电流

Manipulation of Molecular Qubits by Isotope Effect on Spin Dynamics

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CCS Chemistry 2021年第9期3卷 2548-2556页

作者： jing Li Shi-Jie Xiong Chun Li Biaobing Jin Yi-Quan Zhang Shang-Da Jiang Zhong-Wen Ouyang Zhenxing Wang Xing-Long Wu Johan van Tol You Song State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023 National Laboratory of Solid State Microstructures Department of PhysicsNanjing UniversityNanjing 210093 Research Institute of Superconductor Electronics(RISE) School of Electronic Science and EngineeringNanjing UniversityNanjing 210093 Jiangsu Key Laboratory for NSLSCS School of Physical Science and TechnologyNanjing Normal UniversityNanjing 210023 National Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and ApplicationsBeijing Key Laboratory for Magnetoelectric Materials and DevicesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871 Wuhan National High Magnetic Field Center&School of Physics Huazhong University of Science and TechnologyWuhan 430074 National High Magnetic Field Laboratory Florida State UniversityTallahasseeFL 32310

Controlling spin behavior via external stimuli is a key route to develop molecular spintronics devices.Photons,temperature,pressure,chemicals,and electric field are the possible stimuli.Herein,we report a new method,the isotope effect,to control spin behavior in molecule magnet systems.It can not only control the relaxation of magnetization,but also regulate the spin lifetime of quantum coherence.

关键词： molecule-based magnetism molecular qubits isotope effect spin–vibration coupling quantum coherence

Directional terahertz holography with thermally active Janus metasurface

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Light(Science & Applications) 2023年第6期12卷 1162-1171页

作者： Benwen Chen Shengxin Yang Jian Chen jingbo Wu Ke Chen Weili Li Yihui Tan Zhaosong Wang Hongsong Qiu Kebin Fan Caihong Zhang Huabing Wang Yijun Feng Yunbin He Biaobing Jin Xinglong Wu Jian Chen Peiheng Wu Research Institute of Superconductor Electronics(RISE) School of Electronic Science and EngineeringNanjing UniversityNanjing 210023China Purple Mountain Laboratories Nanjing 211111China Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials Hubei Key Laboratory of Polymer MaterialsSchool of Materials Science and EngineeringHubei UniversityWuhan 430062China School of Electronic Science and Engineering Nanjing UniversityNanjing 210023China National Laboratory of Solid State Microstructures and School of Physics Nanjing UniversityNanjing 210093China

Dynamic manipulation of electromagnetic(EM)waves with multiple degrees of freedom plays an essential role in enhancing information processing.Currently,an enormous challenge is to realize directional terahertz(THz)holography.Recently,it was demonstrated that Janus metasurfaces could produce distinct responses to EM waves from two opposite incident directions,making multiplexed dynamic manipulation of THz waves possible.Herein,we show that thermally activated THz Janus metasurfaces integrating with phase change materials on the meta-atoms can produce asymmetric transmission with the designed phase delays.Such reconfigurable Janus metasurfaces can achieve asymmetric focusing of THz wave and directional THz holography with free-space image projections,and particularly the information can be manipulated via temperature and incident THz wave direction.This work not only offers a common strategy for realizing the reconfigurability of Janus metasurfaces,but also shows possible applications in THz optical information encryption,data storage,and smart windows.

关键词： directional Directional asymmetric

Simulation and experiment of vortex transport properties in a Type Ⅱ superconductor with grain boundary

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Science China(Technological Sciences) 2015年第3期58卷 493-498页

作者： JIANG Lai XU WeiWei HUA Tao YU Mei AN DeYue CHEN Jian jin biaobing KANG Lin WU PeiHeng Research Institute of Superconductor Electronics School of Electronic Science and Engineering Nanjing University

We firstly described a simulation model to investigate the influence of grain boundary(GB)on the vortex transport properties in YBCO film.It is found that the size of inhomogeneous area caused by GB as well as the average velocity in transverse and longitudinal directions shows an angular dependence when the angle between the GB and the sample edge varies.We have also studied the impact of magnetic field intensity on dynamic behavior of vortex lattice and found that a lower vortex density makes it difficult for the vortex lattice to transfer from pinning state to flow state.As the magnetic field is decreased beyond a critical value,sharp jumps and strong fluctuations were observed in the I-V curve.Finally,we conducted measurements on a thin film YBa2Cu3O7 with an individual artificial grain boundary to support the simulation process.

关键词：人工晶界输运性质旋涡超导体 YBa2Cu3O7 YBCO薄膜实验仿真

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ID-201单光子计数器计数模型研究

南京大学学报（自然科学版） 2016年第3期52卷 550-557页

作者：曹攀朱广浩金飚兵南京大学电子科学与工程学院南京210093

InGaAs半导体单光子探测器具备探测性能强,集成度高等优势,在光谱分析和量子通信等领域有广泛的应用.本文以ID Quantique公司出品的ID-201半导体单光子计数器为研究对象,结合计数器核心部件雪崩光电二极管的工作原理探究其计数光子时的... 详细信息

InGaAs半导体单光子探测器具备探测性能强,集成度高等优势,在光谱分析和量子通信等领域有广泛的应用.本文以ID Quantique公司出品的ID-201半导体单光子计数器为研究对象,结合计数器核心部件雪崩光电二极管的工作原理探究其计数光子时的内部过程,推导出每秒钟光子计数值和该计数器几个重要参数触发频率(trigger frequency),门脉冲宽度(gate width),门强制关闭时间(dead time),探测效率(detection efficiency)之间的数学表达式.推导过程着重分析了计数门脉冲的关闭效应对光子探测概率的影响.首先利用泊松分布求解光子计数值与探测效率(detection efficiency)之间的关系,然后将计数过程分成两大部分,分析计数结果与门强制关闭时间(dead time)之间关系.求解得表达式后,利用1550nm激光器作为ID-201的输入光源,在各种不同实验条件下,对该表达式的正确性进行了检验.

关键词：单光子计数器计数原理门强制关闭时间雪崩光电二极管