Graphene Modified Plasmonic Sensors

Graphene plasmon polaritons are the hybrids of Dirac quasiparticles and infrared photons, which allows strong light-matter interaction within the tightly confined mode volume. However, plasmon dissipation channels, such as dielectric losses of the substrates, edge scattering, inefficient coupling to free space photon, significantly reduce external quantum efficiency of graphene plasmon. In this work, we demonstrate >60% absorption in a metal-on-graphene hybrid plasmonic structure, with far-infrared transparent spacer material for managing the photon recycling through backside reflectors. The widely tunable infrared plasmon resonance between 10 and 16 μm is achieved through controlling the dimension of periodic metal microstructures. In combination with phase matched spacer thickness, more than 86% absorption is graphene plasmonics can be achieved.