Probing hyperbolic polaritons using infrared attenuated total reflectance micro-spectroscopy

TL;DR

This paper demonstrates that infrared ATR micro-spectroscopy can effectively excite and measure hyperbolic polaritons in hexagonal boron nitride, offering a practical alternative to nanostructuring methods for nanophotonics applications.

Contribution

It introduces a novel ATR micro-spectroscopy technique to probe hyperbolic polaritons, simplifying measurements compared to existing nanostructuring approaches.

Findings

Successfully measured hyperbolic modes in hexagonal boron nitride

Compared optical properties across different isotopic enrichments and thicknesses

Overcame limitations of previous measurement techniques

Abstract

Hyperbolic polariton modes are highly appealing for a broad range of applications in nanophotonics, including surfaced enhanced sensing, sub-diffractional imaging and reconfigurable metasurfaces. Here we show that attenuated total reflectance micro-spectroscopy (ATR) using standard spectroscopic tools can launch hyperbolic polaritons in a Kretschmann-Raether configuration. We measure multiple hyperbolic and dielectric modes within the naturally hyperbolic material hexagonal boron nitride as a function of different isotopic enrichments and flake thickness. This overcomes the technical challenges of measurement approaches based on nanostructuring, or scattering scanning nearfield optical microscopy. Ultimately, our ATR approach allows us to compare the optical properties of small-scale materials prepared by different techniques systematically