Infrared radiation absorption in a wide wavelength range of 3–14 μm mainly based on spatial magnetic plasmon excitation and accumulation in an arrayed nanocavity-shaped metasurface

Abstract

A type of nanocavity-shaped metasurface for intensively absorbing infrared (IR) radiation in a wide wavelength range of 3–14 μm, which is mainly based on spatial magnetic plasmon excitation and accumulation according to an arrayed nanocavity, is proposed. The basic architecture of the metasurfaces is a layered metal-insulator-metal construction through linear arranging of titanium microribbons and also forming an arrayed titanium microcap on the top of a SiO2 layer preshaped over a thin copper film grown on an n-type silicon wafer, respectively. The measurements present that an average IR absorbing efficiency of more than ∼80% can be easily realized by the metasurfaces constructed. The microribbon-based metasurface exhibits polarization sensitivity under x-polarized incidence. A polarization-independent IR absorption can be conducted through the microcap-based metasurface developed continuously. It should be noted that the proposed nanocavity-shaped metasurfaces can, thus, be featured by an intensive IR absorption essentially attributed to the spatial magnetic plasmon excitation and accumulation or a spatial magnetic field resonant superposition and temporary storage in the multiple nanocavities of the metasurfaces designed.