Engineering phonon polaritons in van der Waals heterostructures to enhance in-plane optical anisotropy.

ABSTRACT: Van der Waals (vdW) heterostructures assembled from layers of two-dimensional materials have attracted considerable interest due to their novel optical and electrical properties. Here, we report a scattering-type scanning near-field optical microscopy study of hexagonal boron nitride on black phosphorus (h-BN/BP) heterostructures, demonstrating the first direct observation of in-plane anisotropic phonon polariton modes in vdW heterostructures. Notably, the measured in-plane optical anisotropy along the armchair and zigzag crystal axes exceeds the ratio of refractive indices of BP in the x-y plane. We explain that this enhancement is due to the high confinement of the phonon polaritons in h-BN. We observe a maximum in-plane optical anisotropy of α_max = 1.25 in the f

SUBMITTER: Chaudhary K 

PROVIDER: S-EPMC6461454 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature