Thermal driven wavelength-selective optical switch based on magnetic polaritons coupling

A wavelength-selective optical switch by thermally controlling which has higher transmittance at metallic phase of Vanadium dioxide (VO2) and lower transmittance at insulating phase is presented. By skillfully designing the structure, magnetic polaritons (MPs) are excited to enhance transmission to 0.79 indicating on mode with VO2 at metallic phase. The coupling between two magnetic polariton modes is excited at the same frequency to suppress the transmittance peak to 0.045 indicating off mode with VO2 at insulating phase, demonstrating tunability by over an order of magnitude during phase transition. Magnetic polariton coupling mode is proposed to explain the phenomenon of surpressed transmission and the electromagnetic field distributions confirm it. The proposed optical switch still works well at a large oblique incidence and the resonant frequency does not change with the incident angle. Our study may benefit the microelectronics and infrared active filtering applications. (C) 2020 Elsevier Ltd. All rights reserved.