  We present a hybrid graphene dielectric metasurface design to achieve strong
tunable and modulated transmission at near-infrared (near-IR) frequencies. The
proposed device is constituted by periodic pairs of asymmetric silicon nanobars
placed over a silica substrate. An one-atom-thick graphene sheet is positioned
between the nanobars and the substrate. The in-plane electromagnetic fields are
highly localized and enhanced with this all-dielectric metasurface due to its
zero Ohmic losses at near-IR wavelengths. They strongly interact with graphene
and couple to its properties. Sharp Fano transmission is obtained at the
resonant frequency of this hybrid all-dielectric metasurface configuration due
to the cancelation of the electric and magnetic dipole responses at this
frequency point. The properties of the graphene monolayer flake can be adjusted
by tuning its Fermi energy or chemical potential, leading to different doping
levels and, equivalently, material parameters. As a result, the Q factor and
the Fano resonant transmission spectrum of the proposed hybrid system can be
efficiently tuned and controlled due to the strong light graphene interaction.
Higher than 60 percent modulation in the transmission coefficient is reported
at near-IR frequencies. The proposed hybrid graphene/dielectric nanodevice has
compact footprint, ultrafast speed, and can be easily integrated to the current
CMOS technology. These features would have promising applications to near-IR
tunable filters, faster optical interconnects, efficient sensors, switches, and
amplitude modulators.
