Superconducting Nanostructures for Quantum Detection of Electromagnetic Radiation

superconducting nanostructures;superconducting nanowires;superconducting nanostrips;complex conductivity;enhancement of quantum tunnelling;energy resolving detector;superconducting nanowire single photon detector (SNSPD);multi-layer superconducting nanostructure;vortex;pancake vortex;dark count;photon absorption;quantum efficiency;semi-classical physics;Golubev-Zaikin theory;phase slips;quantum tunnelling;vortex crossing;Mooij-Nazarov duality;terahertz (THz) detector;quantum phase slip (QPS);superconductivity;Electrical and Computer Engineering (Quantum Information)

Jafari Salim, Amir

University of Waterloo

关键词: superconducting nanostructures;    superconducting nanowires;    superconducting nanostrips;    complex conductivity;    enhancement of quantum tunnelling;    energy resolving detector;    superconducting nanowire single photon detector (SNSPD);    multi-layer superconducting nanostructure;    vortex;    pancake vortex;    dark count;    photon absorption;    quantum efficiency;    semi-classical physics;    Golubev-Zaikin theory;    phase slips;    quantum tunnelling;    vortex crossing;    Mooij-Nazarov duality;    terahertz (THz) detector;    quantum phase slip (QPS);    superconductivity;    Electrical and Computer Engineering (Quantum Information);   

Others  :  https://uwspace.uwaterloo.ca/bitstream/10012/8431/1/JafariSalim_Amir.pdf

瑞士|英语

来源: UWSPACE Waterloo Institutional Repository

【 摘 要 】

In this thesis, superconducting nanostructures for quantum detection of electromagneticradiation are studied. In this regard, electrodynamics of topological excitations in 1D superconducting nanowires and 2D superconducting nanostrips is investigated. Topological excitations in superconducting nanowires and nanostrips lead to crucial deviation from the bulk properties. In 1D superconductors, topological excitations are phase slippages of the order parameter in which the magnitude of the order parameter locally drops to zero and the phase jumps by integer multiple of 2pi. We investigate the effect of high-frequency field on 1D superconducting nanowires and derive the complex conductivity. Our study reveals that the rate of the quantum phase slips (QPSs) is exponentially enhanced under high-frequency irradiation. Based on this finding, we propose an energy-resolving terahertz radiation detector using superconducting nanowires. In superconducting nanostrips, topological fluctuations are the magnetic vortices. The motion of magnetic vortices result in dissipative processes that limit the efficiency of devices using superconducting nanostrips.It will be shown that in a multi-layer structure, the potential barrier for vortices to penetrate inside the structure is elevated. This results in significant reduction in dissipativeprocess. In superconducting nanowire single photon detectors (SNSPDs), vortex motionresults in dark counts and reduction of the critical current which results in low efficiencyin these detectors. Based on this finding, we show that a multi-layer SNSPD is capable of approaching characteristics of an ideal single photon detector in terms of the dark count and quantum efficiency. It is shown that in a multi-layer SNSPD the photon couplingefficiency is dramatically enhanced due to the increase in the optical path of the incidentphoton.