Room-temperature readout circuit for superconducting nanowire single-photon detectors

Abstract

The invention discloses a room temperature reading circuit suitable for a superconducting nanowire single-photon detector. The room temperature reading circuit comprises a coaxial line, a power divider, a direct-current bias circuit and a radio frequency amplification circuit which are distributed from a detector to an external detecting instrument, wherein an output signal of the detector is transmitted from a low-temperature working region to a room-temperature environment through the coaxial line; the power divider is used for dividing the output signal into two paths, wherein one path of signal is transmitted to the external detecting instrument through the radio frequency amplification circuit, and the other path of signal is released to a matched load through a radio frequency port of a bias beam in the direct-current bias circuit. By using the room temperature reading circuit, the limit of the capacitance at the front end of a radio frequency amplifier to the maximum metering rate of the detector is eliminated, the detector is prevented from entering a locked state, and the working stability of the detector is effectively improved.

Description

technical field [0001] The invention relates to a readout circuit, in particular to a room temperature readout circuit suitable for superconducting nanowire single photon detectors. Background technique [0002] Superconducting nanowire single-photon detector (superconducting-nanowiresingle-photondetector, SNSPD) is a new type of single-photon detector. The photosensitive part of the detector is composed of nanowires prepared from superconducting thin films, such as niobium nitride thin films. The detector needs to be biased below the superconducting critical current to work. When the nanowire absorbs photons, the superconducting state in the absorbing region is destroyed, which is manifested in the circuit as a sudden drop in the current flowing through the detector. The nanowires then undergo a cooling process to return to their original state. The process of photon absorption by the detector appears on the circuit as a rapidly rising and then exponentially decaying ele...

AI Technical Summary

Problems solved by technology

However, this DC-coupled amplifier needs to be close to the detector chip and work together in a low-temperature environment. This type of amplifier needs to be designed independently, which is difficult in engineering, and it is not easy for practical application and debugging.

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