Development of Superconducting Single-Photon and Photon-Number Resolving Detectors for Quantum Applications

Single-photon detectors based on superconducting thin films have become a viable class of technologies for widespread usage in quantum optics. In this tutorial paper we introduce the key performance metrics required of them for quantum information processing and related fields. We review the latest records achieved by such devices, study technical details regarding recent improvements in superconducting nanowire detectors and transition-edge sensors, and present representative applications in cutting-edge research areas that benefit from these advances.