Probing hyperbolic and surface phonon-polaritons in 2D materials using Raman spectroscopy.

ABSTRACT: The hyperbolic dispersion relation of phonon-polaritons (PhPols) in anisotropic van der Waals materials provides high-momentum states, directional propagation, subdiffractional confinement, large optical density of states, and enhanced light-matter interactions. In this work, we use Raman spectroscopy in the convenient backscattering configuration to probe PhPol in GaSe, a 2D material presenting two hyperbolic regions separated by a double reststrahlen band. By varying the incidence angle, dispersion relations are revealed for samples with thicknesses between 200 and 750 nm. Raman spectra simulations confirm the observation of one surface and two extraordinary guided polaritons and match the evolution of PhPol frequency as a function of vertical confinement. GaSe appears to provide relativ

SUBMITTER: Bergeron A 

PROVIDER: S-EPMC10336144 | biostudies-literature | 2023 Jul

REPOSITORIES: biostudies-literature