Superconducting nanowire single photon detector based on deep silicon etching process and preparation method

Abstract

The invention provides a superconducting nanowire single photon detector based on a deep silicon etching process and a preparation method. The detector comprises an SOI base which is composed of a back substrate, a buried oxygen layer and top silicon in sequence from bottom to top, a first anti-reflection layer which is disposed on the surface of the top silicon, a second anti-reflection layer which is disposed on the surface of the back substrate, a deep groove which penetrates through the second anti-reflection layer, the back substrate and the buried oxygen layer, an optical cavity structure which is disposed on the surface of the first anti-reflection layer, superconducting nanowires which are disposed between the first anti-reflection layer and the optical cavity structure, and a mirror which is disposed on the surface of the optical cavity structure. By etching the deep groove on the substrate, the distance between a coupling optical fiber and the device is narrowed, the use of a long-focus lens in the traditional back-coupling superconducting nanowire single photon detector is avoided, and alignment coupling between the MU head of an optical fiber and the device is facilitated. The problem concerning long-distance focusing in the optical cavity structure and the influence of the Fabry-Perot cavity of the susbtrate on the absorption efficiency are avoided. The absorption efficiency of target wavelength is improved. The detection efficiency of the device is improved.

Description

technical field [0001] The invention belongs to the technical field of light detection, and relates to a superconducting nanowire single-photon detector, in particular to a superconducting nanowire single-photon detector based on a deep silicon etching process and a preparation method thereof. Background technique [0002] Superconducting Nanowire Single Photon Detector (SNSPD) is a new type of single photon detection device developed in recent years, which can realize high-efficiency single photon detection from visible light to near infrared. Due to its advantages such as high quantum efficiency, low dark count, high detection rate, and low time jitter, SNSPD has been rapidly applied in applications such as quantum information technology, laser communication, satellite-to-earth ranging, bioluminescent detection, and depth imaging. [0003] SNSPD mainly uses low-temperature superconducting ultra-thin film materials, such as NbN, Nb, NbTiN, WSi, etc. The typical thickness i...

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Problems solved by technology

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a superconducting nanowire single photon detector based on deep silicon etching process and its preparation method, which is used to solve the problem of superconducting nanowire single photon detection in the prior art. The absorption efficiency of the detector is low, in order to solve the long-distance focusing of the back light to the NbN nanowire, a special long-focus lens is required, and the influence of the substrate Fabry-Perot cavity on the absorption efficiency, etc.

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