Identification of graphene layers by dielectric grating: giant enhancement of visibility

摘要

The layer number of graphene plays a critical role in determining its electronic and optical properties; thus the identification of the layer number of graphene is strongly required in experiments. Here, through rigorous coupled-wave analysis, we propose a one-dimensional dielectric grating structure as a promising platform for enhancing the optical contrast of graphene. It is found that the optical contrast of monolayer (bilayer and trilayer) graphene can surprisingly reach 56% (74% and 82%) at normal incidence in the well-designed dielectric grating structure, whose value is around 12 (7 and 6) times than that of monolayer (bilayer and trilayer) graphene supported by a one-dimensional photonic crystal. Our results expand the horizon of the visibility field and indicate its potential for practical identification of the layer number of two-dimensional layered materials in experiments. (C) 2018 Optical Society of America