Abstract
In this paper, we introduce and investigate the characteristics of a new metamaterial perfect absorber (MPA) consisting of a metal-dielectric-metal (MDM) functional stack having a gold hexagonal annular nano-array as a top layer. With finite difference time domain (FDTD) method, we investigate the optical absorption spectra of such structures. Evaluation techniques such as average absorption efficiency, ripples percentage, and relative absorption bandwidth are studied. We found that, the out of phase interaction coupling between the localized and propagating surface plasmons can be tuned to boost the performance of the broadband MPA. The proposed MPA exhibits an average absorption efficiency of 97.5% with 4.5% ripples percentage in the visible regime 400-700 nm. The magnetic and electric fields, polarization, current density, and heat absorption distributions are introduced for the proposed MPA. These distributions provide a better insight to the absorption behavior based on both macroscopic and microscopic perspectives. By extension, a honeycomb structure was presented as an imperfection from the hexagonal one to emphasize localized and propagating surface plasmons interaction rule.