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

Abstract

The invention discloses a high-speed superconducting nanowire single-photon detector (SNSPD) with a strong absorption structure and a preparation method of the high-speed SNSPD with the strong absorption structure. The SNSPD is capable of further improving the photon absorptivity of superconducting nanowires based on an incident medium with a high refractive index and an air cavity structure. Compared with the prior art and according to the high-speed SNSPD, under the condition that the nanowires are made of superconducting ultrathin membranes with the same material and the same thickness, nearly 100% of absorptivity can be realized through a lower duty ratio, and the difficulty of electron beams in the exposure steps is reduced greatly, thereby particularly being more beneficial to the preparation of the ultrathin nanowires; and meanwhile, by adopting a silicon on insulator (SOI) substrate, the high-quality growth of the superconducting ultrathin membranes can be ensured simultaneously without affecting the intrinsic quantum efficiency of the detector. In addition, under the condition that the large effective detection area is ensured equally, as the total length of the required nanowires is reduced obviously, the maximum counting rate of the detector can be improved, and the probability of occurring defects during preparation process is decreased notably.

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 ability in the visible and infrared bands, ultra-high count rate, low dark count, and small time jitter, it has attracted more and more attention, especially its quantum efficiency in the near-infrared band. Both the count rate and the highest count rate have exceeded the existing avalanche photodiodes based on compound semiconductor materials, making them the most powerful candidate detectors in the fi...

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.

US 2012 / 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 used under the conditions of 4nm thick and 50% duty cycle NbN nanowires. Achieving an absorption rate 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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