PHOTON TUNNELING VIA COUPLING GRAPHENE PLASMONS WITH PHONON POLARITONS OF HEXAGONAL BORON NITRIDE IN RESTSTRAHLEN BANDS

The photon tunneling probability is the most important thing in near-field radiative heat transfer (NFRHT). This work study the photon tunneling via coupling graphene plasmons with phonon polaritons in hexagonal boron nitride (hBN). We consider two cases of the optical axis of hBN along z-axis and x-axis, respectively. We investigate the NFRHT between graphene-covered bulk hBN, and compare it with that of bare bulk hBN. Our results show that in Reststrahlen bands, the coupling of graphene plasmons and phonon polaritons in hBN can either suppress or enhance the photon tunneling probability, depending on the chemical potential of graphene and frequency. This conclusion holds when the optiacal axis of hBN is either along z-axis or x-axis. The findings in this work not only deepen our understanding of coupling mechanism between graphene plasmons with phonon polaritons, but also provide a theoretical basis for controlling photon tunneling in graphene covered hyperbolic materials.