Quantum Tomography of Superconducting Single Photon Detectors

Nanowire superconducting single photon detectors (SSPDs) consist of a thin (~ 4 to 6 nm) and narrow (~ 50 to 200 nm) superconducting wire biased close to the critical current. Operating conditions are such that the absorption of one or more photons locally transfers the detector to its normal state, which then results in a detectable electrical pulse. SSPDs are versatile detectors that operate in a wide wavelength range (from UV to mid-infrared) with almost ...