Lithography-free flexible perfect broadband absorber in visible light based on an all-dielectric multilayer structure

Opt Lett. 2020 Oct 1;45(19):5464-5467. doi: 10.1364/OL.404423.

Abstract

A flexible broadband absorber based on an all-dielectric multilayer structure is proposed to get an average absorbance of 97.4%, covering the whole visible light. Additionally, such high absorption presents an extraordinary angular tolerance of up to ±50. Due to the single broadband resonance in the highly lossy Fabry-Perot (F-P) cavity and the intrinsic loss property of Ge, the proposed multilayer structure achieves the broadband absorption effect. Furthermore, the simple all-dielectric multilayer configuration requires no noble metal, making the lithography-free, large-scale, cost-effective manufacturing process feasible. Meanwhile, the good substrate adaptation facilitates its preparation on a flexible substrate. Accordingly, a three-dimensional object covered by the proposed flexible absorber can be treated as a two-dimensional black hole, revealing the effect of stealth. The proposed perfect absorber shows potentials for camouflage coating, solar energy collection, flexible optoelectronics, and other fields.