Design of a high-performance tunable absorber based on composite dielectric layer metamaterial

Abstract

A tunable metamaterial absorber based on hybrid structure design strategy is suggested and numerically verified. An absorption peak (82.5%, at resonance wavelength 1.52 μm) is achieved at room temperature without Fermi energy, which is derived from local surface plasma (LSP) modes excited on edges of metal particles. The adjustability of this structure is derived from two structural components: vanadium dioxide (VO2) particles are temperature sensitive and graphene films are sensitive to Fermi energy and Fermi energy difference. Therefore, the resonant properties of this structure can be modulated by varying the temperature, energy, or energy difference. Simulated results reveal that two new absorption peaks are achieved at the resonance wavelengths 1.82 and 2.09 μm, which are both derived from the LSP modes excited on edges of VO2 particles. Moreover, both new absorption peaks are enhanced with the simulated temperature increased. Three optimized values of the carrier mobility μ are achieved: VO2 particles support region 8200 cm2 / ( V · s ) , metal particle support region 8800 cm2 / ( V · s ) , and suspended region 230,000 cm2 / ( V · s ) . The absorption peak is enhanced and shifted to shorter wavelength with the Fermi energy level increasing, while the absorption peak is reduced and shifted to longer wavelength with the Fermi energy difference reducing.