Open AccessDouble-sided and omnidirectional absorption of visible light in tapered dielectric nanostructure coated with non-noble metal
Author(s) -
Shanpu Shen,
Jie Tang,
Yu Jiang,
Lei Zhou,
Yun Zhou
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.024989
Subject(s) - materials science , optoelectronics , optics , dielectric , nanostructure , cladding (metalworking) , visible spectrum , absorption (acoustics) , nanotechnology , physics , metallurgy , composite material
The common complex architecture constitutes the major bottleneck of optical absorber operating on broadband spectrum. Here we demonstrate a super absorber consisting of tapered dielectric nanostructure coated with a thin-layer of non-noble metal chromium on flexible poly(ethylene terephthalate) substrate. The proposed device yields double-sided, omnidirectional, and polarization-independent absorption over the entire visible spectrum with an average efficiency more than 90% at normal incidence, and 80% at a tilt incident angle of 60°. It can be easily realized by nanoimprinting lithography combined with physical vapor deposition technique. Theoretical analysis demonstrates that the superior optical performance is ascribed to the non-resonant light absorption by using the metal-covered, closed-packed tapered nanostructure via adiabatic nanofocusing of the metal-dielectric-metal (MDM) guided modes excited by scattering of the gradually changing nanostructure. For the cost-effective fabrication and material strategy, the super absorber has potential applications in a wide range of passive and active photonic devices, including inkless printing, harvesting solar energy, as well as thermal emitter and optical detector.