  Metasurfaces, together with graphene plasmonics, have become prominent for
the emissivity control in thermal engineering, both passively through changing
the geometric parameters and packing density of the metasurfaces, and actively
through graphene gating or doping. We demonstrate a graphene-nanowire coupled
plasmonic metasurface utilizing the hybrid localized surface plasmon modes of
the nanowire array and graphene. The nanowire array makes the hybrid surface
plasmon mode localized, allowing a free-space excitation. The single layer
graphene, via the gating between the underneath mirror and a top electrode, can
actively tune the spectral emissivity by almost 90%. In addition, the hybrid
plasmon mode provides an extra degree of freedom to modulate the p-polarized
emissivity with a five-fold enhancement, especially for large emission angles.
