Enhanced absorption in heterostructures with graphene and truncated photonic crystals

TL;DR

This paper demonstrates that combining graphene with truncated photonic crystals significantly enhances optical absorption across the visible spectrum, with broad angular and polarization insensitivity, verified through theory and experiments.

Contribution

It introduces a heterostructure design that greatly improves absorption in graphene using truncated photonic crystals, supported by both theoretical modeling and experimental validation.

Findings

Absorption in heterostructures is nearly four times higher than in graphene alone.

Enhanced absorption occurs across a wide range of incident angles and polarizations.

Experimental results agree well with theoretical predictions.

Abstract

We theoretically and experimentally investigate the optical absorption properties of heterostructures composed of graphene films and truncated photonic crystals (PCs) in the visible range. The experimental results show that the absorption of the heterostructure is enhanced greatly in the whole forbidden gap of PCs compared with that of graphene alone. The absorption is enhanced over a wide angle of incidence for both transverse electric (TE) and transverse magnetic (TM) polarizations. The enhanced absorption band broadens for TE polarization but narrows for TM polarization as the incident angle increases. In the forbidden gap of the PCs, the maximum absorptance of the heterostructures is nearly four times of that of bare graphene films for arbitrary incident angles and polarizations. The optical experiments are in excellent agreement with the theoretical results.