Research Progress of Superconducting Microstrips Single-Photon Detectors

Superconducting microstrips single-photon detectors (SMSPDs) are a novel type of single-photon sensor based on superconducting thin films patterned into micrometer-scale strip widths. Compared with superconducting nanowire single-photon detectors (SNSPDs), SMSPDs not only substantially lower the fabrication dependence on high-precision electron-beam lithography, but also exhibit lower kinetic inductance, higher bias current, and weaker polarization sensitivity. These advantages pave a new route toward superconducting single-photon detection systems with large active areas and low dark-count rates. Because of their performance, SMSPDs exhibit tremendous application potential in cutting-edge fields such as quantum communication, LiDAR, dark-matter searches, and high-energy particle detection. Accordingly, this paper provides a systematic review of recent advances in SMSPD research, covering the underlying physical mechanisms, material systems, geometrical design, readout circuitry, and application domains. Firstly, this review elaborates on the photon response mechanism of SMSPDs and clarifies its correlation with vortex dynamics. Secondly, this review categorizes the superconducting materials used for SMSPD fabrication and analyzes the influences of characteristic thin-film parameters on device performance. Furthermore, this work concludes the evolution and optimization strategies of geometrical design and readout circuit schemes for SMSPDs, and presents the current application status. Finally, we offer perspectives on its future development trajectory. This review provides a foundation in physical mechanisms and design guidance for the development of large active area SMSPDs with high efficiency and low dark counts.