Efficient Broadband Truncated-Pyramid-Based Metamaterial Absorber in the Visible and Near-Infrared Regions

We present a design of an ultra-broadband metamaterial absorber in the visible and near- infrared regions. The unit cell structure consists of a single layer of metallic truncated-pyramid resonator-dielectric-metal configuration, which results in a high absorption over a broad wavelength range. The absorber exhibits 98% absorption at normal incidence spanning a wideband range of 417-1091 nm, with >99% absorption within 822-1054 nm. The broadband absorption stability maintains 95% at large incident angles up to 40 degrees for the transverse electric (TE)-mode and 20 degrees for the transverse magnetic (TM)-mode. Furthermore, the polarization-insensitive broadband absorption is presented in this paper by analyzing absorption performance with various polarization angles. The proposed absorber can be applied for applications such as solar cells, infrared detection, and communication systems thanks to the convenient and compatible bandwidth for electronic THz sources.