Bulk ReSe2: record high refractive index and biaxially anisotropic material for all-dielectric nanophotonics

TL;DR

This paper demonstrates that bulk ReSe2 has a record high refractive index exceeding 5 and exhibits extreme biaxial anisotropy, making it a promising material for all-dielectric nanophotonics in the near-infrared range.

Contribution

The study provides the first experimental measurement of ReSe2's high refractive index and biaxial anisotropy, supported by theoretical predictions, highlighting its potential for nanophotonic applications.

Findings

ReSe2 has a refractive index >5 in near-infrared.

ReSe2 exhibits extreme biaxial optical anisotropy.

Experimental data agrees with density functional theory predictions.

Abstract

We show that bulk rhenium diselenide, ReSe2 is characterized by record high value of the refractive index exceeding 5 in near-infrared frequency range. We use back focal plane reflection spectroscopy to extract the components of the ReSe2 permittivity tensor and reveal its extreme biaxial anisotropy. We also demonstrate the good agreement between the experimental data and the predictions of the density functional theory. The combination of the large refractive index and giant optical anisotropy makes ReSe2 a perspective material for all-dielectric nanophotonics in the near-infrared frequency range.