Ultra-broadband perfect absorber based on sub-grating structure

AbstractThis paper introduces an ultra-broadband perfect absorber. The absorber comprises just two layers. By introducing sub-grating structures in the groove of the rectangle grating, a broadband absorber is realized. The proposed structure operates in the wavelength range of 420nm-1543 nm, exhibiting an absorptivity greater than 90%. To enhance our comprehension of the physical mechanism behind broadband absorption, we analyze the distributions of current density, electric field, and magnetic field within the structure. The ultra-broadband absorption is achieved through multiple resonances of the structure. Additionally, the absorber demonstrates good absorption performance at large incident angles. By modifying the proposed structure to possess centrosymmetry, the absorber becomes impervious to incident waves with varying polarization angles. Owing to the simple structure, the absorber may have a wider range of applications, including photovoltaic devices and light-emitting devices.KEYWORDS: Broadbandabsorptionmetamaterialgrating Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by the post-funded project of Hebei Normal University for Nationalities: [Grant Number HQ2022001].