Photo-excited separated tuning for the frequency and magnitude of dual-band absorption in the terahertz regime

Abstract Introducing tuning materials into metasurfaces is a crucial development trend for dynamic nanodevices. In this paper, we achieve the separate tuning for the frequency and magnitude of dual-band absorption in a photo-excited metasurface in the terahertz regime. By tuning the conductivity of the embedded photo-excited silicon, the two absorption peaks shift by 0.33 THz and switch to zero from near unity, respectively. In contrast, the absorption spectrum of x -polarized waves shows insensitivity to the variation of silicon conductivity. The LC equivalent circuit model is used to demonstrate the resonance frequencies of absorption peaks, which agree well with simulation results. This photo-excited Si based metasurface has wide potential applications in dynamic terahertz devices, such as modulators and frequency selectors.