Strong optical force acting on a dipolar particle over a multilayer substrate

TL;DR

This paper demonstrates a theoretical and numerical method to significantly enhance optical forces on nano-sized particles using resonant coupling with a multilayer substrate, enabling improved particle manipulation.

Contribution

It introduces a novel mechanism leveraging flat-band plasmon modes in multilayer substrates to amplify optical forces on dipolar particles.

Findings

Resonant particle-substrate coupling greatly increases optical force.

Flat-band plasmon modes are key to force enhancement.

Potential applications in nanoparticle manipulation.

Abstract

Optical forces acting on nano-sized particles are typically too small to be useful for particle manipulation. We theoretically and numerically demonstrate a mechanism that can significantly enhance the optical force acting on a small particle through a special type of resonant particle-substrate coupling. The resonance arises from the singular behavior of the particle's effective polarizablity in the presence of a metal-dielectric-metal multilayer substrate. We show that this phenomenon is closely related to the existence of a flat-band plasmon mode supported by the multilayer substrate.