A multiple-resonator approach for broadband light absorption in a single layer of nanostructured graphene.

The interaction between two-dimensional (2D) materials and light is rather weak due to their ultrathin thickness. In order for these emerging 2D materials to achieve performances that are comparable to those of conventional optoelectronic devices, the light-material interaction must be significantly enhanced. An effective way to enhance the interaction is to use optical resonances. Efficient light absorption has been demonstrated in a single layer of graphene based on a variety of resonators. However, the bandwidth of the absorption enhancement is always narrow, which limits its application for optoelectronic devices. In order to broaden the enhancement of light-material interaction, here we propose a multiple-resonator approach based on nanostructured graphene. These nanostructures having different geometry support resonances at different frequencies. Owing to their deep subwavelength sizes, graphene resonators can be closely packed in space, resulting in a high optical density of states, which enables the broadband light absorption.