Strong plasmon − phonon coupling for graphene/ hBN thermal emitter atomic system

The surface plasmon polaritons of graphene coupled with hyperbolic phonon polaritons of hexagonal boron nitride (hBN) have been considered as the ideal platform to enhance thermal emitter, which provides a powerful tool to implement energy conversion and thermal management. The conventional approaches for the strong plasmon − phonon coupling rely on the bulk hBN materials, which usually have a large footprint and display little tunability. Recently, hBN atomic emitter has been demonstrated that its peak emissivity is hopefully as high as the bulk hBN emitters. Here, we propose a graphene/hBN thermal emitter atomic system to flexibly modify the spectral emissivity by the strong plasmon − phonon coupling effect, which can be separately manipulated by the graphene width, chemical potential of graphene, number of hBN atomic layers and hBN width. Our scheme is hopefully realizing a comparable function with the bulk graphene/hBN system. Furthermore, we employ coupled oscillator model involving three oscillators to investigate the energy exchange and mode evolution between three plasmon − phonon hybridized modes, providing an excellent agreement with simulated and theoretical results. Consequently, optically manipulating plasmon − phonon interaction opens a broad design space for the spectral emissivity control, which explores the mid-infrared applications of advanced graphene thermo-optoelectronics and electrically driven thermal emitters.