A mid-infrared biaxial hyperbolic van der Waals crystal
arXiv:1809.03432
Abstract
Hyperbolic media have attracted much attention in the photonics community, thanks to their ability to confine light to arbitrarily small volumes and to their use for super-resolution applications. The 2D counterpart of these media can be achieved with hyperbolic metasurfaces, which support in-plane hyperbolic guided modes thanks to nanopatterns which, however, pose significant fabrication challenges and limit the achievable confinement. We show that thin flakes of the van der Waals material α-MoO3 can support naturally in-plane hyperbolic polariton guided modes at mid-infrared frequencies without any patterning. This is possible because α-MoO3 is a biaxial hyperbolic crystal, with three different Restrahlen bands, each for a different crystal axis. Our findings can pave the way towards new paradigm to manipulate and confine light in planar photonic devices.
References in corpus (7)
- Electromagnetic Wave Propagation in Media with Indefinite Permittivity and Permeability Tensors
- Sub-diffractional, volume-confined polaritons in a natural hyperbolic material: hexagonal boron nitride
- Hyperbolic phonon-polaritons in boron nitride for near-field optical imaging
- Infrared hyperbolic metasurface based on nanostructured van der Waals materials
- Broadband Purcell effect: Radiative decay engineering with metamaterials
- Manipulation and steering of hyperbolic surface polaritons in hexagonal boron nitride
- Conical diffraction and the dispersion surface of hyperbolic metamaterials