Gate-tunable polariton reflection in hBN-graphene heterostructures
Siyuan Dai
Auburn University – Auburn, Alabama, USA
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The variation of optical momentum determines light propagation across material interfaces. Evident momentum mismatch at the two sides of the interface results in inefficient energy transfer due to the lack of phase matching, thereby causing light reflection or scattering. In this work, we demonstrate an electrically tunable polaritonic reflector in hBN-graphene heterostructures. By varying the polariton momentum at one side of the heterostructure through back-gating graphene, the propagating hyperbolic phonon polaritons can either transmit or get reflected at the interface. The tunable polariton reflection phenomena are imaged in real space by scattering-type scanning near-field optical microscopy. Our nano-polaritonic experimental data are supported by electromagnetics simulations using the Finite Element Method. The gate-tunable polariton reflection in hBN-graphene heterostructures presented in this work holds promises for practical device developments in polaritonic nano-optical circuits and nanoscale heat/energy control.
Email: sdai@auburn.edu