Atomic-scale confinement of optical fields

TL;DR

This paper demonstrates atomic-scale confinement of optical fields using gold nanorod dimers with sub-nanometer gaps, enabling extreme light-matter interactions and opening new avenues in quantum optics and sensing.

Contribution

The study introduces a self-assembly method to create gold nanorod dimers with atomically-defined gaps below 0.5 nm, demonstrating atomic-scale optical confinement.

Findings

Observation of Coulomb splitting >800 meV in scattering experiments

Successful fabrication of nanorod dimers with sub-0.5 nm gaps

Potential applications in quantum optics and ultra-sensitive sensing

Abstract

In the presence of matter there is no fundamental limit preventing confinement of visible light even down to atomic scales. Achieving such confinement and the corresponding intensity enhancement inevitably requires simultaneous control over atomic-scale details of material structures and over the optical modes that such structures support. By means of self-assembly we have obtained side-by-side aligned gold nanorod dimers with robust atomically-defined gaps reaching below 0.5 nm. The existence of atomically-confined light fields in these gaps is demonstrated by observing extreme Coulomb splitting of corresponding symmetric and anti-symmetric dimer eigenmodes of more than 800 meV in white-light scattering experiments. Our results open new perspectives for atomically-resolved spectroscopic imaging, deeply nonlinear optics, ultra-sensing, cavity optomechanics as well as for the realization of novel quantum-optical devices.