Enhanced Light-Matter Interaction in B-10 Monoisotopic Boron Nitride Infrared Nanoresonators

TL;DR

This paper demonstrates that monoisotopic B-10 hexagonal-boron nitride nanoresonators exhibit significantly enhanced phonon-polariton lifetimes and Q factors, enabling improved nanophotonic sensing and strong light-matter coupling at infrared frequencies.

Contribution

It introduces monoisotopic B-10 h-BN nanoresonators with increased phonon-polariton lifetimes and Q factors, advancing nanophotonic applications and sensing capabilities.

Findings

50% average improvement in Q factor over natural h-BN

Effective sensing of nanometric-thick molecular films

Achieved strong coupling between molecular vibrations and phonon-polaritons

Abstract

Phonon-polaritons, mixed excitations of light coupled to lattice vibrations (phonons), are emerging as a powerful platform for nanophotonic applications. This is because of their ability to concentrate light into extreme sub-wavelength scales and because of their longer phonon lifetimes than their plasmonic counterparts. In this work, the infrared properties of phonon-polaritonic nanoresonators made of monoisotopic B-10 hexagonal-boron nitride (h-BN) are explored, a material with increased phonon-polariton lifetimes compared to naturally abundant h-BN due to reduced photon scattering from randomly distributed isotopes. An average relative improvement of 50% in the nanoresonators Q factor is obtained with respect of nanoresonators made of naturally abundant h-BN. Moreover, the monoisotopic h-BN nano-ribbon arrays are used to sense nanometric-thick films of molecules, both through surface-enhanced absorption spectroscopy and refractive index sensing. In addition, strong coupling is achieved between a molecular vibration and the phonon-polariton resonance in monoisotopic h-BN ribbons.