Fabrication of a superconducting niobium nitride hot electron bolometer for single-photon counting

Abstract

Superconducting photodetectors offer an interesting alternative to traditional photon counting systems such as photomultiplier tubes and avalanche photodiodes for applications in optical quantum information processing. In these superconducting devices, different mechanisms are exploited to detect the photon absorption, depending on the type of detector (transition edge sensor, superconducting tunnel junction and hot electron bolometer (HEB)). The first two are briefly presented; more emphasis is given on HEB elaboration made with very thin superconducting NbN films due to their unique capability of fast single-photon detection. Constraints on NbN HEB elaboration and on electronic transport properties are presented in the perspective of further improvement of the quantum efficiency in the near-infrared.