Optical Single-Photon Detection in Micrometer-Scale NbN Bridges

The success of superconducting single-photon detectors has recently led to theoretical analysis of the impact of photons on a current-carrying superconductor, accompanied by the emergence of resistance due to vortices. Based on this analysis, a device unlike the standard long, narrow variety is developed, enabling operation close to the intrinsic critical pair-breaking current of the superconductor. These devices, which can be as wide as a few μm, clearly show single-photon detection for optical wavelengths from 408 to 1550 nm, making them compatible with optical fibers and promising for next-generation large-area detectors for quantum optics applications.