Coupling of plasmonic nanoparticles to their environments in the context of van der Waals-Casimir interactions

TL;DR

This study demonstrates how the interaction between gold nanoparticles can be precisely tuned and observed using advanced experimental techniques, providing insights into van der Waals-Casimir forces at the nanoscale.

Contribution

It introduces an experimental method to control and measure nanoparticle interactions in situ, aligning experimental results with FDTD calculations for van der Waals-Casimir interactions.

Findings

Spectral shifts depend on particle separation and polarization.

Good agreement between experimental data and FDTD simulations.

Technique offers potential for studying fundamental nanoscopic forces.

Abstract

We present experiments in which the interaction of a single gold nanoparticle with glass substrates or with another gold particle can be tuned by in-situ control of their separations using scanning probe technology. We record the plasmon resonances of the coupled systems as a function of the polarization of the incident field and the particle position. The distinct spectral changes of the scattered light from the particle pair are in good agreement with the outcome of finite difference time-domain (FDTD) calculations. We believe our experimental technique holds promise for the investigation of the van der Waals-Casimir type interactions between nanoscopic neutral bodies.