Ultrabroadband Plasmonic Absorber Based on Biomimetic Compound Eye Structures

Abstract

A perfect absorber based on plasmonic resonance for a variety of remarkable properties has motivated vivid research during the last few decades. However, most of the perfect absorbers had been focused on polarization-insensitive and narrow-band absorption, due to the existence of a theoretical limit. It is urgent to extend the optical properties of absorbers with omnidirectional and broadband performances to satisfy the requirements for practical application. Hence, we adopt a new convenient, energy-saving, and environmentally friendly silk mediated layer nanoimprint technology to obtain biomimetic moth eye structures with omnidirectional and broadband perfect absorption. Experimental and simulation results show that the absorbers can realize the absorption efficiency to a maximum of 99% over the entire visible spectrum for angles up to 70° from normal. In addition, it also exhibits excellent bidirectional absorptive characteristic of this design. We anticipate that this absorber may have greatly potential application in the photovoltaic and thermal imaging area.

Keywords

• Compound eye structure
• nanoimprint lithography
• silk fibroin
• perfect absorber.