Graphene enhanced absorption entailed by the electromagnetic field localization in a photonic structure

Since its discovery and proper isolation, graphene has become a popular material with outstanding mechanical, electrical and optical properties, that make it attractive for different potential applications. Graphene has a constant optical absorption of 2.3% in the range of visible and near-infrared ranges [1], which make it an ideal material for the design of photonic and optoelectronic devices, like photodetectors, optical modulators and sensors [2]. Active photonic devices, require a strong light-matter interaction, often happening in a very small volume of absorbing material, especially when integrated photonic chips are envisaged. For this purpose, graphene layers are ideal candidates. However, the absorption given by a single graphene layer on a homogeneous substrate is usually insufficient for most practical sensing applications. Further enhancement of the absorption using material engineering is crucial for the new optical sensing devices.