High-Performance Ti Transition-Edge Sensor-based Photon-Number Resolving Detectors

• Published in: Journal of low temperature physics Vol. 214; no. 3-4; pp. 100 - 105
• Main Authors: Li, Peizhan, Zhong, Jiaqiang, Zhang, Wen, Wang, Zheng, Ma, Qingxiao, Feng, Zhifa, Miao, Wei, Ren, Yuan, Li, Jing, Yao, Qijun, Shi, Shengcai
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.02.2024; Springer Nature B.V
• Subjects: Antireflection coatings; Characterization and Evaluation of Materials; Condensed Matter Physics; Critical temperature; Detectors; Diameters; Energy resolution; Magnetic Materials; Magnetism; Numerical aperture; Photons; Physics; Physics and Astronomy; Transition-edge sensor; Quantum efficiency; Optimal filtering; Single-photon detector
• ISSN: 0022-2291; 1573-7357
• DOI: 10.1007/s10909-023-03015-8

Superconducting transition-edge sensor (TES)-based single-photon detectors with high detection efficiency, low dark count rate and photon-number resolving capability are suitable for many scientific applications. We have developed a high-performance Ti TES-based single-photon detector at a working wavelength of about 1550 nm. The TES with a critical temperature of around 200 mK has an active area of 10 μm × 10 μm, which is manually aligned to an ultra-high numerical aperture fiber with a mode field diameter of 4 μm, leading to a nearly perfect coupling efficiency. The Ti TES integrated into an optical cavity consisting of a dielectric mirror and an anti-reflection coating exhibits an absorption efficiency of 97% at 1550 nm. The fabricated TES shows an energy resolution of 0.21 eV using a 1540 nm pulsed source, and it can resolve up to 20 photons. The measured system detection efficiency is 95% ± 0.4%.