Strong interaction between graphene and localized hot spots in all-dielectric metasurfaces

The active photonics based on the two-dimensional material graphene have attracted a great deal of interest for developing tunable and compact optical devices with high efficiency. Here, we integrate graphene into the Fano-resonant all-dielectric metasurfaces consisting of silicon split resonators, and systematically investigate the strong interaction between graphene and the highly localized hot spots inside feed gaps in the near infrared regime. The numerical results show that the integrated graphene can substantially reduce the Fano resonance due to the coupling effect between the intrinsic absorption of graphene with enhanced electric field in the localized hotspot. With the manipulation of the surface conductivity via varying Fermi level and the layer number of graphene, the Fano resonance strength obtains a significant modulation and is even switched off. This work provides a great degree of freedom to tailor light-matter interaction at the nanoscale and opens up avenues for actively tunable and integrated nanophotonic device applications, such as optical biosensing, slow light and enhanced nonlinear effects. (paper)