Superconducting nanowire single-photon detector with mid-infrared high-light absorption characteristic

Abstract

The superconducting nanowire single-photon detector with the mid-infrared high-light absorption characteristic comprises a nanowire layer, a silicon dioxide cavity, a distributed Bragg reflector and a substrate which are sequentially arranged from top to bottom, and the nanowire layer adopts a single-layer NbN nanowire or a double-layer NbN nanowire. Then, the minimum value of the light absorptivity within the wavelength range of 3-5 microns is used as a target function, optimal solutions of the thicknesses of the silicon dioxide cavity, the high-refractive-index film of the DBR and the low-refractive-index film of the DBR in the initial structure are sought through particle swarm optimization / PSO, and SNSPD design with the 3-5 microns broadband high light absorptivity and the good in-band flatness characteristic is achieved. When incident light enters vertically, in a target wavelength range of 3-5 microns, the minimum value of the light absorptivity of the optimized single-layer NbN nanowire structure is 0.526, the maximum value of the light absorptivity of the optimized single-layer NbN nanowire structure is 0.779, and the in-band flatness can be as low as 0.253; the minimum value and the maximum value of the double-layer NbN nanowire structure respectively reach 0.748 and 0.974, and the in-band flatness can be as low as 0.226.

Description

technical field [0001] The invention belongs to the technical field of infrared photoelectric detectors, and relates to a superconducting nanowire single-photon detector with mid-infrared high light absorption characteristics. Background technique [0002] Superconducting nanowire single-photon detectors / SNSPDs have been rapidly developed and widely used in the past two decades due to their low dark count, wide response spectrum, small time jitter, and fast repetition speed. In various related cutting-edge technology fields, such as long-distance quantum communication, single-photon imaging, etc. With the continuous emergence of new demands, the research on the photon response mechanism and polarization-insensitive structure design of SNSPD is also deepening. The SNSPD with high detection efficiency in the mid-infrared is receiving more and more attention because of its important application value in such fields as spectral analysis and astronomical observation. [0003] T...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a superconducting nanowire single-photon detector with high light absorption characteristics in the mid-infrared, which solves the problem that it is difficult to simultaneously ensure high peak light absorption rate and better light absorption efficiency in the design of the detector broadband light absorption efficiency in the prior art. The problem of in-band flatness

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