A Polarization-insensitive Dual-band Plasmonic Metamaterial Absorber for a Sensor Application

Abstract

A polarization-insensitive dual-band plasmonic metamaterial absorber is proposed, which is constituted by merely the metal nano-cylinder and a continuous metallic ground separated by a middle dielectric layer. Two resonance peaks with over 99% absorbance derived from `the fundamental resonance and the surface lattice resonance are realized. In addition, we demonstrated that proposed dual-absorber retain nearly perfect absorbance for all polarization angles of both TE and TM modes on normal incidence. It is different from previous work that the dual-frequency response is obtained by combining two subunits of different sizes. Moreover, a first-order diffraction mode of grating predicted the resonance frequency of the proposed absorber. Importantly, the second absorption peak result from surface lattice resonance with narrow line-width has large sensitivity perform and high quality factor, which has significant potential in the application of biosensors and monitoring.