Graphene polaritonic crystal

Lin Xiong

Photonic crystals are media with periodically varying optical properties. Photonic crystals enable exquisite control of light propagation in integrated optical circuits and also emulate advanced physical concepts. However, common photonic crystals directly pattern the optical medium and thus are unfit for in-operando on/off controls. In this dissertation, we introduced, fabricated, and studied the properties of graphene polaritonic crystals. Our polaritonic crystal system consists of a pristine sheet of graphene in a back-gated platform with nano-structured gate insulators. We employed scattering-type scanning near-field optical microscopy (s-SNOM) to study the novel properties of polaritons propagating in the polaritonic crystal. We demonstrated the formation of a polaritonic bandgap, variations of the polaritonic local density of states, and the emergence of polaritonic domain wall...