Twisted polaritonic crystals in thin van der Waals slabs

Polaritons – hybrid light–mater excitations – are very appealing for the confinement of light at the nanoscale. Recently, a particular interest has been focused on thin anisotropic slabs of van der Waals (vdW) materials supporting polaritons with hyperbolic dispersion, which can exhibit ultrahigh mo...

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Bibliographic Details
Authors: Capote Robayna, Nathaniel, Matveeva, Olga G., Volkov, Valentyn S., Alonso-González, Pablo, Nikitin, Alexey Y.
Format: article
Status:Versión aceptada para publicación
Publication Date:2022
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/286881
Online Access:http://hdl.handle.net/10261/286881
Access Level:Open access
Description
Summary:Polaritons – hybrid light–mater excitations – are very appealing for the confinement of light at the nanoscale. Recently, a particular interest has been focused on thin anisotropic slabs of van der Waals (vdW) materials supporting polaritons with hyperbolic dispersion, which can exhibit ultrahigh momenta and strongly directional in-plane propagation and thus promise novel nano-optical applications in a planar geometry. However, the excitation and manipulation of in-plane hyperbolic polaritons have not yet been well studied and understood. Here, twisted polaritonic crystals (PCs) are introduced – lattices with periods comparable to the polaritons wavelength rotated with respect to the natural vdW crystal axes – to efficiently excite and control in-plane hyperbolic polaritons. A general analytical theory valid for an arbitrary PC made in a thin biaxial slab is developed and the excitation of Bragg resonances tunable by the twisting angle is demonstrated. The findings open novel avenues for both fundamental studies of PCs in vdW crystals and the development of midinfrared sensing and photodetection applications.