Strong Confinment of optical fields using localised surface phonon polaritons in cubic Boron Nitride

TL;DR

This paper demonstrates the strong confinement of optical fields using localized surface phonon polaritons in cubic boron nitride nanostructures, showing potential for advanced infrared optical devices.

Contribution

It reports the fabrication of cBN nanostructures supporting high-Q localized surface phonon polaritons, a novel approach for infrared photonic applications.

Findings

Localized surface PhPs observed with quality factors over 38

cBN nanostructures support high-frequency optical phonons

Potential applications in infrared communication and sensing

Abstract

Phonon polaritons (PhPs) are long-lived electromagnetic modes that originate from the coupling of infrared photons with the bound ionic lattice of a polar crystal. Cubic-Boron nitride (cBN) is such a polar, semiconductor material, which due to the light atomic masses can support high frequency optical phonons. Here, we report on random arrays of cBN nanostructures fabricated via an unpatterned reactive ion etching process. FTIR reflection spectra suggest the presence of localized surface PhPs within the Reststrahlen band, with quality factors in excess of 38 observed. These can provide the basis of next generation infrared optical components like antennas for communication, improved chemical spectroscopies, and enhanced emitters, sources and detectors.