Coupling-induced perfect absorption in TMD-based metasurface

Abstract

Excitons in transition metal dichalcogenides (TMDs) exhibit high oscillator strength and intrinsic losses. This property makes TMD materials favorable for studying light–matter interactions and enhancing light absorption. Here, we propose a strategy to achieve significantly enhanced absorption in a TMD-based metasurface. We demonstrate a nanodisk array composed of bulk TMD materials, enabling the excitation of Mie resonances that couple efficiently to the intrinsic excitons. We show that the coupling of both the magnetic and electric components of the Mie mode to the intrinsic excitons leads to the Kerker effect, resulting in significantly enhanced broadband absorption. Importantly, by introducing an additional metallic back reflector, dual-band perfect absorption can be achieved through suppression of the transmission channel. Unlike previously reported approaches using critical coupling conditions, the present coupling-induced enhancement of absorption can be sustained over a large range of incidence angles. With the help of a metallic back reflector, dual-band perfect absorption can be achieved at the self-hybridized polariton states. Our design is expected to be useful for high-compact polaritonic devices and may pave the way for advanced light-harvesting applications.