Demonstration of a Superconducting Nanowire Single-Photon Detector using Adiabatic Quantum-Flux-Parametron Logic in a 0.1-W Gifford-McMahon Cryocooler

Superconducting nanowire single-photon detectors (SSPDs or SNSPDs) have superior performance and are thus used for many applications, such as quantum information and laser communications. Lately, much effort has been spent on the development of multi-pixel SSPD arrays to achieve single-photon-level imaging. SSPD arrays require efficient readout schemes that reduce the number of coaxial cables for reading out the SSPD pixels. In a previous study, we proposed a readout interface using adiabatic quantum-flux-parametron (AQFP) logic, which digitizes the information of an SSPD at cryogenic temperature. In this study, we show the first demonstration of an SSPD that is read out by the AQFP readout interface placed in the same 0.1-W Gifford-McMahon cryocooler. The measurement results show that the AQFP readout interface reads out the SSPD with low error rates. Also, it is found that the temperature of the sample stage does not change even after the AQFP readout interface is turned on, which indicates that the power and current required for the AQFP readout interface are sufficiently low for the implementation using a compact cryocooler.