Improving detection efficiency of Ti-based superconducting transition edge sensors with optical cavity

25 Jul 2019, 17:45
1h 15m
Piazza Città di Lombardia (Milano)

Piazza Città di Lombardia

Milano

Piazza Città di Lombardia, 1, 20124 Milano MI
Poster Low Temperature Detector for quantum technologies and other frontiers Poster session

Speaker

Prof. Wen Zhang (Purple Mountain Obsevatory, CAS)

Description

Superconducting transition edge sensors (TESs) have demonstrated high detection efficiency and photon-number resolving capability, making TESs attractive in quantum information. The detection efficiency is determined by several factors: fiber-to-detector coupling, absorption of photons in superconducting films, and internal quantum efficiency. The optical absorption of titanium film at the wavelength of 1550 nm, is approximately 30%, determined by its refractive index. Embedding the Ti-based TES in an optical structure to enhance its absorption is an effective approach for improving detection efficiency. We integrated the TES with an optical cavity, consisting of 16-layer dielectric reflection mirror and 4-layer anti-reflection layer, and studied the effect of fabricated optical cavity on the detection efficiency of Ti TES single photon detectors. The critical temperature (Tc) is decreased to 260 mK after deposition of antireflection layer from its original Tc of 350 mK. The detection efficiency (i.e., the ratio of the detected power to input power) was increased up to 30% , thanks to the enhancement of photon absorption by adding the optical cavity.

Less than 5 years of experience since completion of Ph.D N
Student (Ph.D., M.Sc. or B.Sc.) N

Primary authors

Mr Yue Gen (Purple Mountain Observatory,CAS) Prof. Wen Zhang (Purple Mountain Obsevatory, CAS) Mr Pei-Zhan Li (Purple Mountain Observatory,CAS) Dr Jia-Qiang Zhong (Purple Mountain Observatory,CAS) Dr Zheng Wang (Purple Mountain Observatory,CAS) Prof. Wei Miao (Purple Mountain Observatory,CAS) Prof. Yuan Ren (Purple Mountain Observatory,CAS) Prof. Qi-Jun Yao (Purple Mountain Observatory) Prof. Sheng-Cai Shi (Purple Mountain Observatory,CAS)

Presentation Materials