Q-factor and wavelength adjustable ultra-perfect absorption under critical coupling through epsilon-near-zero-based absorbers.

ABSTRACT: Perfect absorption with adjustable Q factor and wavelength is essential in both theory and application. To address this issue, a structure composed of an epsilon-near-zero (ENZ)- SiO₂ grating and a multilayer dielectric structure was designed. In the structure, the intrinsic loss is related to the ENZ thickness, while the external leakage depends on the grating parameters. By adjusting the ENZ film thickness, the intrinsic loss rate was tuned to match the external leakage rate corresponding to different grating parameters, realizing the critical couplings with different Q factors and wavelengths. Under critical coupling, the absorption rate reached a maximum of 99.999%, demonstrating ultra-perfect absorption. The Q factor was adjusted from 4350 to 35800, and the absorption wavel

SUBMITTER: Li YD 

PROVIDER: S-EPMC11319591 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature