Superconducting single-photon detector with phase grating and manufacturing method for superconducting single-photon detector with phase grating

Abstract

The invention discloses a superconducting single-photon detector with a phase grating and a manufacturing method for the superconducting single-photon detector with the phase grating. The superconducting single-photon detector with the phase grating is characterized in that the phase grating is arranged on a nanowire area of a conventional superconducting single-photon detector based on niobium nitride. The grating height of the phase grating is odd-number times the thickness corresponding to the phase of the wavelength pi of incident light. The phase grating on the nanowire area generates the focusing interference effect on light beams, niobium nitride nanowires are located at the focal position, and therefore the absorption efficiency of the niobium nitride nanowires to photons is improved. Simulation results show that the superconducting single-photon detector with the phase grating has the quite high detection efficiency in multiple frequency bands of visible light and infrared light, and the photon absorption efficiency is as high as 72% when the wavelength is 850 nm.

Description

technical field [0001] The invention relates to a highly sensitive single-photon or extremely weak light signal detector, in particular to a superconducting single-photon detector based on niobium nitride, which can be applied to the detection of single-photon or extremely weak light signals in visible light and near-infrared bands . Background technique [0002] The superconducting nanowire single photon detector is currently the most popular single photon detector structure in the world. It uses a very thin superconducting film (usually with a thickness of 4nm to 8nm) to prepare a nanowire with a width of 80nm. Below the critical temperature, a bias current lower than the superconducting critical current is passed. When the photons hit the nanowire and are absorbed by the nanowire to form a heat island, the current density on the nanowire is greater than the superconducting current density, thereby quenching and generating a voltage The pulse, picked up by the readout cir...

AI Technical Summary

Problems solved by technology

However, at present, due to the low absorption efficiency of the niobium nitride film itself, the system detection efficiency of the superconducting single photon detector is low.

At the same time, since the detection rate of the superconducting nanowire single photon detector is related to the dynamic inductance of the nanowire, the larger the dynamic inductance, the lower the detection rate, and the dynamic inductance is linearly related to the length of the nanowire. Considering the detection rate and reducing the dynamic inductance , the length of the nanowire, that is, the effective detection area is required, so it is difficult to prepare a large-area superconducting single-photon detector

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