Bi-tunable absorber based on borophene and VO2 in the optical telecommunication band

Abstract

We propose a bi-tunable absorber based on a single layer of borophene, silica grating, and vanadium dioxide ( V O 2 ) in the telecommunication band. The numerical simulation results show that the perfect absorption can be achieved at 1353 nm when the electron density of the borophene layer is n = 3.5 × 1 0 19 m − 2 and the V O 2 layer is in the metallic phase because the borophene layer is assisted by grating and the Fabry–Perot resonator is formed by the absorber. More importantly, the absorption peak and absorption amplitude can be independently tuned by regulating the electron density of the borophene layer and the insulator-metal transition (IMT) of the V O 2 layer. The absorption peak can be tuned in a wide range by altering the electron density while the absorption is maintained above 0.95 in the optical telecommunication band. The absorption amplitude also can be dynamically adjusted from 0.61 to 0.95 by the IMT of the V O 2 layer when the electron density of the borophene layer is n = 2.5 × 1 0 19 m − 2 . In addition, for oblique incidence from 0° to 40°, the proposed absorber can maintain high absorption performance of more than 0.95. The absorber achieves dynamic regulation of the absorption peak and amplitude by two independent methods, which provide guidance for the research of intelligent and tunable devices.