Broadband perfect absorption achieved by double-square-slotted Ti3 C2 Tx layer

Abstract There are a few reports on broadband optical MAs using a whole unpatterned Ti₃C₂Tx layer or patch-type Ti₃C₂Tx resonators, and this paper presents a broadband optical MA using the slotted 30-nm-thick Ti₃C₂Tx layer. The proposed MA can achieve the absorptivity over 90% in the wavelength range of 674–1021 nm. More significantly, the absorptivity beyond 98% is achieved in the wavelength range of 763–965 nm. The function of the slotted 30-nm-thick Ti₃C₂Tx layer is demonstrated by the comparison between the proposed MA and a similarly constructed structure with the top material replaced by gold. The absorption mechanism is investigated by the distribution of electric field, in which the local surface plasmon resonance (SPR) is quantitatively identified to contribute to the enhancement of absorption. Moreover, the proposed MA is insensitive to incident angles within 60°. Furthermore, the simulated results as well as the design robustness is demonstrated by the calculated ones using the multi-reflection interference theory.