Design and Analysis of Quantum Ring Photodetector Enhanced by Metallic Slits

Effects of subwavelength metallic slits on the absorption efficiency using finite element method (FEM) are investigated. A Fabry-Perot (FP) cavity with Au slits and Aufilm acting as two reflectors is utilized to support resonance mode in multispectral bands. With considering this special feature, we propose an enhanced quantum ring photodetector in the terahertz range of the electromagnetic spectrum. Electric field distribution at different modes is studied and dependencesof the resonant absorption behaviours on the device parameters are shown. Compared with the conventional quantum ringphotodetector the designed photodetector provides about 47 times absorption enhancement at the frequency of 7.1 THz