  Surface plasmon resonance (SPR) has been intensively investigated and widely
exploited to trap the incident light and enhance absorption in the
optoelectronic devices. The availability of graphene as a plasmonic material
with strong half-metallicity and continuously tunable surface conductivity
makes it promising to dynamically modulate the absorption enhancement with
graphene-based metamaterials. Here we numerically demonstrate tunable light
trapping and absorption enhancement can be realized with graphene-based
complementary metamaterials. Furthermore, we also explore the polarization
sensitivity in the proposed device, in which case either TM or TE plane wave at
the specific wavelength can be efficiently absorbed by simply manipulating the
Fermi energy of graphene. Therefore, this work can find potential applications
in the next generation of photodetectors with tunable spectral and polarization
selectivity in the mid-infrared and terahertz (THz) regimes.
