Affiliation:
1. Fudan University
2. ShanghaiTech University
3. Shanghai Qi Zhi Institute
4. Yiwu Research Institute of Fudan University
Abstract
Superconducting photodetection offers a wide spectral coverage ranging from the microwave to X-ray, and in the short wavelength range, single photon sensitivity can be achieved. However, in the longer wavelength infrared region, the system detection efficiency is low due to the lower internal quantum efficiency and weak optical absorption. Here, we utilized the superconducting metamatieral to enhance the light coupling efficiency and reach nearly perfect absorption at dual color infrared wavelengths. Dual color resonances arise from hybridization of local surface plasmon mode of the metamaterial structure and the Fabry-Perot-like cavity mode of metal (Nb)-dielectric (Si)-metamatieral (NbN) tri-layer structure. We demonstrated that, at the working temperature of 8 K slightly below T
C
∼8.8 K, this infrared detector exhibits the peak responsivity of 1.2 × 106 V/W and 3.2 × 106 V/W at two resonant frequencies 36.6 THz and 104 THz, respectively. The peak responsivity is enhanced about ∼8 and ∼22 times, respectively, compared to that of non-resonant frequency (67 THz). Our work provides a way to harvest infrared light efficiently and hence improve the sensitivity of superconducting photodetectors in multispectral infrared range, which may find promising applications in thermal image and gas sensing etc.
Funder
National Natural Science Foundation of China
Science and Technology Commission of Shanghai Municipality
Subject
Atomic and Molecular Physics, and Optics