Advances and Perspectives in Single Photon Detectors: Principles, Materials, Cooling Systems, and Applications

Abstract Efficient detection of ultra‐weak optical signals, particularly at the single‐photon level, is critical for the advancement of technologies such as LiDAR and quantum communication. Conventional linear optical detectors exhibit insufficient sensitivity to meet the rigorous demands of these applications. Single‐photon detectors, with their unparalleled sensitivity and ultrafast response, offer substantial promise. However, their performance is limited by factors including material properties, device architecture, and environmental noise. Current research efforts are focused on optimizing materials, refining device designs, and enhancing cooling technologies, yet a systematic theoretical framework remains lacking. This review addresses these challenges by exploring the fundamental principles, material innovations, and cooling strategies essential to overcoming existing limitations. It emphasizes the inherent trade‐off in achieving high detection efficiency, low dark count rates, and minimal afterpulse probability. An integrated optimization approach is proposed, aligning front‐end device design with back‐end application needs, balancing detection efficiency, dark count rates, and temporal resolution. This strategy aims to facilitate the practical deployment of high‐performance single‐photon detectors.