Spectral, spatial and polarization-selective perfect absorbers with large magnetic response for sensing and thermal emission control

Abstract

Spectral, spatial, and polarization selective perfect absorption of light in periodic metal-dielectric-metal nanoslits, each of which supporting a single electric-field anti-symmetric surface mode, is systematically studied. Our numerical analysis shows complete absorption of p-polarized light associated with large magnetic field enhancement at wavelengths from the visible to the mid-infrared range and roles played by the geometrical parameters of the structure. This understanding is then applied to the design of the structure with multiple nanoslits in a period that exhibits complete absorption at multiple wavelengths. Semi-analytical expression of the zeroth mode reflectance is derived, which shows a good agreement with numerical simulations and yields clear insight into the underlying physics of light-matter interactions in the structure.