Quantum Efficiency in small area Transition-Edge Sensors (TESs)

Mikihisa Matsuyama, Mamoru Endo, Casper R. Breum +5 more

Chiara Portesi, E. Taralli, L. Lolli +2 more

Transition edge sensors (TESs) with high energy resolution (ΔE) at telecommunication wavelengths have been realized in the last years for application to experiments of quantum optics and quantum information. In these fields, lasers with repetition rate of the order of 50 MHz are usually applied and hence TES with recovery times lower than 20 ns would be desirable. To this aim, Ti TESs with area ranging between 1 μm × 1 μm and 2 μm × 2 μm are fabricated and characterized, to study the effects of the different sizes of active areas and critical temperatures on the energy resolutions and on the response times. Titanium TESs have been fabricated by thermal evaporation and Electron Beam Lithography technique on Si/SiN substrates, and they have been electrically and optically characterized. The experimental data have been analyzed and correlated to the detector geometrical parameters. The superconducting transitions of TESs with areas down to 1 μm × 1 μm result to be affected by lateral proximity effects of Nb wirings. Ti TESs with critical temperature of 470 mK show response time of about 150 ns and energy resolution of 0.16 eV.

Mohsen Izadyari, Ali Pedram, Lea Gassab +2 more

Yue Geng, Wen Zhang, Zheng Wang +4 more

Superconducting transition-edge sensor single photon detectors (TESs) are attractive in quantum optics and quantum information experiments owing to their high quantum efficiency and photon number resolving capability. In this paper, we present the design and DC characteristics of superconducting Ti TESs with different overlapping area between Ti microbridge and Nb leads.

Bongs, Kai

Takeshi Jodoi, Tetsuya Tsuruta, Takahiro Kikuchi +4 more

This study developed transition-edge sensors (TESs), which can achieve high detection efficiency and fast response time through an optimized optical cavity design. Their suitability for optical quantum information processing was confirmed. Furthermore, we developed TESs with two different sensitive area sizes—8 × 7 ţm2, 12 × 11 ţm2—and systematically evaluated their performances. By employing a titanium (Ti)/gold (Au) bilayer with a relatively high transition temperature as the sensitive element, we achieved a fast total response time—defined as the sum of the rise and decay times—of ∼160 ns. Furthermore, the optical cavity structure—predicted by simulations to achieve a photon absorptance of 99.9% at 1550 nm—yielded measured system detection efficiencies of 94.7% ± 0.62% for the 8 × 7 ţm2 TES and 99.0% ± 0.60% for the 12 × 11 ţm2 TES. Photon response measurements indicate an energy resolution of 0.20 eV for the 8 × 7 ţm2 TES and 0.37 eV for the 12 × 11 ţm2 TES. These results establish that the proposed TESs are the fastest and most efficient devices reported to date. The proposed devices offer a high detection efficiency, high count rate, and accurate photon-number resolution. Therefore, they provide a breakthrough platform for scalable fault-tolerant quantum information processing and enable significant advances in experimental quantum optics.