Superconducting nanowire single photon detector and its preparation method

Abstract

The invention belongs to the technical field of light detection, and relates to a superconducting nanowire single-photon detector and a preparation method thereof. The superconducting nanowire single photon detector includes: a substrate; a reflective layer located on the surface of the substrate; a detection layer located on the surface of the reflective layer for detecting photons, and the detection layer includes several superconducting nanowires A wire unit; a matching layer, at least located on the surface of the superconducting nanowire unit and covering the superconducting nanowire unit, at least for reducing the polarization extinction ratio of the superconducting nanowire unit; The photon detector is provided with a matching layer covering the superconducting nanowire unit, which can use the matching layer to reduce the polarization extinction ratio of the superconducting nanowire single photon detector, thereby reducing the polarization sensitivity of the superconducting nanowire single photon detector and expanding The application field of the superconducting nanowire single photon detector improves the accuracy and repeatability of its detection.

Description

technical field [0001] The invention belongs to the technical field of light detection, and relates to a superconducting nanowire single-photon detector and a preparation method thereof. Background technique [0002] Superconducting nanowire single-photon detectors (SNSPDs) are highly sensitive photodetectors that utilize photon absorption to excite non-equilibrium hotspots in superconducting nanowires for single-photon detection. Generally, it is made of ultra-thin (~5nm) ultra-fine (~100nm) superconducting material, which has the properties of high detection efficiency, low dark count, small time jitter and fast response rate. With the gradual deepening of people's understanding of SNSPD from mechanism to performance, the performance of SNSPD has been improved rapidly. Recent research results show that: in the near-infrared band, the performance of SNSPDs in all aspects is significantly better than other types of single-photon detectors. At present, the basic and applied...

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Problems solved by technology

[0005] The polarization sensitivity of SNSPD is not conducive to practical application

In the coherent light detection of conventional optical fiber links, the polarization direction of the incident light can be adjusted by an external polarization controller to achieve high-efficiency detection. In the case of incoherent light detection, the polarization state of photons is uncontrollable. Due to the different absorption efficiencies of SNSPDs for different polarization states of light, the detection efficiency of SNSPDs is limited by the absorption efficiency of TM polarization states of light, making SNSPDs unable to exert high detection efficiency. advantage, which is not conducive to the widespread application of SNSPD

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