Characteristics of Ti transition-edge sensor based superconducting single-photon detectors

TES-based superconducting single-photon detectors with different dimensions between 5 mu mx5 mu m and 20 mu mx20 mu m were developed. The measured system detection efficiency(eta sys)is 72% at 1550 nm,and energy resolution (Delta E)is 0.26 eV by integrating an optical cavity during the TES fabrication. Based on the two-fluid model,we extract the key parameters(i. e. ,temperature sensitivity,current sensitivity,heat capacity,et. al)of Ti TES-based superconducting single-photon detectors with different dimensions,and calculate the effective response time and Delta E,which are consistent with the measured ones. The obtained results show that it's possible to realize high eta sys and Delta E by optimizing TES dimen- sion and critical temperature,paving the way for high performance single-photon detectors at telecommunication band.