Tuning of mid-infrared absorption through phonon-plasmon-polariton hybridization in a graphene/hBN/graphene nanodisk array

In this paper, we utilize a heterostructured graphene/hBN/graphene nanodisk array to implement an electrically tunable absorber in and out of the Reststrahlen band (RSB) region of hBN. Tuning of phonon-type resonance absorption in the RSB region is achieved through phonon-plasmon-polariton hybridization. The hybrid phonon mode enabled a 290 nun shift of the resonant wavelength, and the sensitivity of absorption peak to the electrical control is 362.5 nm/eV. Simultaneously, the nearly perfect absorption is obtained in the condition of high chemical potential of graphene. Moreover, the plasmon polaritons are strongly modified by phonon polaritons of hBN, so the FWHM of absorption peaks out of the RSB region reduce to 45-49 nm, and the maximum Q of absorption reaches 220.44 at E-F=0.65 eV, which is paving a way toward coherent emission at the atmospheric transparent band. Importantly, graphene-assisted hyperbolic phonon polaritons of hBN will enable future phonon devices with high optical performance and wide tunability. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

A heterostructured graphene/hBN/graphene nanodisk array was used to create an electrically tunable absorber within and outside the Reststrahlen band of hBN, achieving tuning of resonance absorption through phonon-plasmon-polariton hybridization. The hybrid phonon mode enabled significant shifts in resonant wavelength and sensitivity to electrical control.