  The active photonics based on the two-dimensional material graphene has
attracted enormous interests for developing the 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 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 works provides a great degree of
freedom to tailor light-matter interaction at the nanoscale and opens up the
avenues for actively tunable and integrated nanophotonic device applications,
such as the optical biosensing, slow light and enhanced nonlinear effects.
