High-speed snspd with strong absorption structure and its preparation method

Abstract

A high-speed SNSPD with a strong absorption structure and a preparation method thereof. The SNSPD is based on a high-refractive index incident medium and an air cavity structure, which can further increase the photon absorption rate of superconducting nanowires. Compared with the prior art, the present invention uses the same material and Under the condition of thick superconducting ultra-thin films made into nanowires, the absorption rate close to 100% can be achieved with a lower duty cycle, which greatly reduces the difficulty of the electron beam exposure step, especially for ultra-fine nanowires It is more favorable for the preparation of the superconducting film, and the use of SOI substrate can ensure the high-quality growth of the superconducting film at the same time, without affecting the intrinsic quantum efficiency of the detector. In addition, under the condition of ensuring the same large effective detection area, Since the total length of the required nanowires is significantly reduced, the maximum count rate of the detector can be increased, and the probability of defects occurring during the fabrication process is significantly reduced.

Description

technical field [0001] The invention belongs to the field of single-photon detection, is suitable for realizing ultra-fast and high-efficiency single-photon detection in the near-infrared band, and relates to a high-speed SNSPD with a strong absorption structure and a preparation method thereof. Background technique [0002] In recent years, G.N.Gol'tsman et al., "Picosecond superconducting single-photon optical detector," Applied Physics Letter, vol.79, pp.705–707, 2001. The Superconducting Nanowire Single Photon Detector (SNSPD) , due to its excellent single-photon detection capability, ultra-high count rate, low dark count, and small time jitter in the visible and infrared bands, it has attracted more and more attention, especially in the near-infrared band. Both the efficiency and the highest count rate have surpassed the existing avalanche photodiodes based on compound semiconductor materials, making them the most powerful candidate detectors in the fields of quantum co...

AI Technical Summary

Problems solved by technology

If you want to further increase the absorption rate, you need to increase the duty cycle or thickness of the nanowire, but the former puts forward more stringent requirements on sample preparation, while the latter will lead to a decrease in the intrinsic quantum efficiency of the detector.

US2012 / 0077680A1 "Nanowire-based detector" K.K.Berggren, X.Hu, D.Masciarelli et al. The method of increasing the absorption rate based on nano-antennas can be realized under the conditions of 4nm thick and 50% duty cycle NbN nanowires. The absorption rate is close to 100%, but this scheme also puts forward relatively high requirements on sample preparation, and the final experimental results show that its yield is not high

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