Modulation of a multi-band tunable metamaterial with metal disk array

Abstract

A multi-band metamaterial with vanadium dioxide (VO2) layer is proposed, manufactured, and measured in the terahertz (THz) band. Two absorption peaks (P1 and P2) are excited at 33.88 THz (60% amplitude, and 0.7 THz full width at half maximum (FWHM)) and 37.94 THz (76% amplitude, and 1.62 THz FWHM) at room temperature. The P1 peak is achieved based on the local surface plasmon (LSP) modes resonance, while the P2 peak is revealed by the LSP modes and the Ohmic loss of the bottom metal layer. Both P1 and P2 can be enhanced through increasing structural parameter D or reducing structural parameter P during experiments. As the temperature rises to T = 340k, the peaks P3 and P4 are obtained at 11.9 THz (80.1% amplitude, and 2.24 THz FWHM) and 23.52 THz (85.2% amplitude, and 3.83 THz FWHM). The resonance properties of P1 and P2 peaks are insensitive to temperature. The P3 peak is obtained based on the Fabry-Perot resonance between the metal disk and the lower VO2 layer, while the P4 peak is revealed by the ultra-thin Fabry-Perot resonance between the metal disk and the upper VO2 layer. The original resonance properties of the proposed metamaterial absorber can be kept stable, while the new absorption performances can be controlled through changing temperature.