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A High-Efficiency Broadband Superconducting Nanowire Single-Photon Detector with a Composite Optical Structure

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Chinese Physics Letters 2015年第3期32卷 145-148页

作者：顾敏康琳张蜡宝赵清源郏涛万超徐睿莹杨小忠吴培亨 research institute of superconductor electronics School of Electronic Science and EngineeringNanjing University

Superconducting nanowire single-photon detectors （SNSPDs） with a composite optical structure composed of phase-grating and optical cavity structures are designed to enhance both the system detection efficiency and the response bandwidth. Numerical simulation by the finite-difference time-domain method shows that the photon absorption capacity of SNSPDs with a composite optical structure can be enhanced significantly by adjusting the parameters of the phase-grating and optical cavity structures at multiple frequency bands. The absorption capacity of the superconducting nanowires reaches 70%, 72%, 60.73%, 61.7%, 41.2%, and 46.5% at wavelengths of 684, 850, 732, 924, 1256, and 1426nm, respectively. The use of a composite optical structure reduces the total filling factor of superconducting nanowires to only 0.25, decreases the kinetic inductance of SNSPDs, and improves the count rates.

关键词： length A High-Efficiency Broadband Superconducting Nanowire Single-Photon Detector with a Composite Optical Structure

Dependence of Switching Current Distribution of a Current-Biased Josephson Junction on Microwave Frequency

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Chinese Physics Letters 2015年第4期32卷 118-121页

作者：翟计全李永超史建新周渝李小虎许伟伟孙国柱吴培亨 research institute of superconductor electronics School of Electronic Science and EngineeringNanjing University

We investigate the distribution of the switching current of a current-biased Josephson junction （CBJJ） and its dependence on the microwave frequency using two theoretical methods, one of which is the quantum trajectory method and the other is the master equation method. Both the methods show that the distribution of the switching current of CBJJ will exhibit double peaks in a certain range of microwave frequency if proper microwave power is given, and the gap between the two peaks will increase with the microwave frequency. The obtained results can be used to identify the energy difference of the ground and first excited states in a Josephson junction for any bias current.

关键词： Dependence of Switching Current Distribution of a Current-Biased Josephson Junction on Microwave Frequency

A New Quantity to Characterize Stochastic Resonance

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Chinese Physics Letters 2015年第9期32卷 119-122页

作者：王育昕翟计全许伟伟孙国柱吴培亨 research institute of superconductor electronics School of Electronic Science and EngineeringNanjing University

In a double-well system, we investigate theoretically the population distribution of a particle perturbed by a weak sinusoidal signal with a Gaussian white noise accompanied. Our numerical simulation shows that the probability of the particle staying in the right potential well, Pn, exhibits an extreme value at specific noise intensity D depending on the frequency of the sinusoidal signal, which is a key feature of stochastic resonance. This is confirmed by calculating the power spectrum of the output signal, in which the extreme value of the amplitude locates at the same noise intensity. These results provide us with a new way to quantify the stochastic resonance by measuring the population distribution of the particle.

关键词： A New Quantity to Characterize Stochastic Resonance

Quasi-particle injection into YBa2Cu3O7-δ micro-bridge

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Science Bulletin 2003年第11期48卷 1161-1164页

作者： SUN Guozhu,WU Peiheng,CAI Weixing,JI Zhengming,XU Weiwei,KANG Lin,YANG Senzu research institute of superconductor electronics Department of electronic Science and Engineering Nanjing University research institute of superconductor electronics Department of electronic Science and Engineering Nanjing University research institute of superconductor electronics Department of electronic Science and Engineering Nanjing University research institute of superconductor electronics Department of electronic Science and Engineering Nanjing University research institute of superconductor electronics Department of electronic Science and Engineering Nanjing University research institute of superconductor electronics Department of electronic Science and Engineering Nanjing University research institute of superconductor electronics Department of electronic Science and Engineering Nanjing University Nanjing 210093 China Nanjing 210093 China Nanjing 210093 China Nanjing 210093 China Nanjing 210093 China Nanjing 210093 China Nanjing 210093 China

Several types of quasi-particle injections into YBa2Cu3O7-d (YBCO) micro-bridge have been studied, re- vealing the quasi-particle non-equilibrium effect, the current superposition effect and the heating effect. The current gain抯 dependence on temperatures indicates that supercon- ductivity of YBCO is really suppressed by quasi-particle injection. We propose a new type of quasi-particle injection which turns out to be a promising candidate for interface between superconductor and semiconductor circuits.

关键词： quasi-particle injection high temperature superconductor.

Fabrication of Al/AlO_x/Al Josephson junctions on silicon and sapphire substrates using a cold-development technique

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Science China(Physics,Mechanics & Astronomy) 2019年第6期62卷 75-80页

作者： Wei Chen JiaZheng Pan ZuYu Xu YangYang Lv XianJing Zhou XueCou Tu Jun Li GuoZhu Sun HuaBing Wang research institute of superconductor electronics (RISE) Nanjing University

In order to obtain high-quality superconducting qubits, we employed a cold-development technique, using temperatures down to-20°C, to fabricate Al/AlOx/Al Josephson junctions. Cold development greatly reduced the sensitivity of the electron-beam resist to the developer, eliminated molecules of the electron-beam resist at trench edges, and improved the repeatability and reliability of the nanopatterning process. The fabricated samples have well-defined geometries and increased dose margins, with lateral sizes of 100 nm×100 nm on both silicon and sapphire substrates. Together with the bridge-free fabrication method we used in these experiments, we believe that the cold-development technique can play an important role in quantum information technology that employs superconducting qubits.

关键词： Josephson junction cold development electron-beam lithography insulating substrates

Tunable coplanar waveguide resonator with nanowires

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Chinese Physics B 2015年第4期24卷 425-430页

作者：周渝郏涛翟计全汪橙钟先茜曹志敏孙国柱康琳吴培亨 research institute of superconductor electronics (RISE) Nanjing University

A tunable superconducting half-wavelength coplanar waveguide resonator （CPWR） with Nb parallel nanowires - 300 nm in width embedded in the center conductor was designed, fabricated, and measured. The frequency shift and the amplitude attenuation of the resonance peak under irradiation of 404-nm pulse laser were observed with different light powers at 4.2 K. The RF power supplied to such a CPWR can serve as current bias, which will affect the light response of the resonator.

关键词： coplanar waveguide niobium resonator superconducting nanowire

Influence of introducing Zr,Ti,Nb and Ce elements on externally solidified crystals and mechanical properties of high-pressure die-casting Al–Si alloy

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 147-153页

作者： Junjie Li Wenbo Yu Zhenyu Sun Weichen Zheng Liangwei Zhang Yanling Xue Wenning Liu Shoumei Xiong Center of Materials Science and Engineering School of Mechanical and Electronic Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Traffic&Transportation Engineering Central South UniversityChangsha 410075China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile *** can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated ***,the development of non-heat treatment Al alloys is becoming the hot *** addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of *** achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and *** influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic *** results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased ***,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical *** introduction of Ce resulted in the poisoning effect and reduced mechanical properties.

关键词： aluminium alloy high-pressure die-casting externally solidified crystals non-heat treatment

Dynamics of a qubit—TLS system under resonant microwave driving

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Chinese Science Bulletin 2014年第21期59卷 2547-2551页

作者： Jianxin Shi Weiwei Xu Guozhu Sun Jiquan Zhai Zhican Du Lin Wang Tao Hua Jian Chen Lin Kang Peiheng Wu research institute of superconductor electronics (RISE) School of Electronic Science and EngineeringNanjing University

We demonstrate the effect of different coupling strengths between a microscopic two-level system(TLS)and a microwave field on the dynamics of a qubit—TLS system when the bipartite system is subject to resonant microwave *** beating with a different TLSmicrowave coupling strength is demonstrated in ***,quantified by the concurrence between the qubit and TLS,both for pure states and mixed states,is *** decoherence is considered,entanglement of the bipartite system oscillates with damping and exhibits entanglement sudden death and/or entanglement sudden death and revival.

关键词： TLS 微波场系统驾驶共振量子位耦合强度突然死亡

Terahertz narrow bandstop, broad bandpass filter using double-layer S-shaped metamaterials

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Science China(Information Sciences) 2013年第12期56卷 132-138页

作者： LIANG LanJu JIN BiaoBing WU JingBo ZHOU GaoChao ZHANG YongGang TU XueCou JIA Tao JIA XiaoQing CAO ChunHai KANG Lin XU WeiWei CHEN Jian College of Optoelectronics Engineering Zaozhuang University research institute of superconductor electronics (RISE) School of Electronic Science and EngineeringNanjing University

In this study,double-layer S-shaped metamaterials(MMs)are analyzed by terahertz time-domain *** materials exhibit narrow bandstop and broad bandpass transmission properties at both horizontal and vertical electric-feld polarizations.A 117%increase in the unloaded quality factor is experimentally observed for these *** center frequency is approximately 0.45 THz,with a 3-dB bandwidth of 0.52 THz from 0.20 to 0.72 THz at normal *** measured average insertion loss is 0.5 dB with a ripple of 1 *** results show that double-layer S-shaped MMs are efective in designing tunable terahertz devices.

关键词： metamaterial terahertz flter double-layer S-shaped material transmission