Localized vibrational modes in optically bound structures

TL;DR

This paper demonstrates that optical binding can create stable one-dimensional particle lattices with localized vibrational modes, driven by long-range optical forces rather than disorder or nonlinearity.

Contribution

It provides analytical and numerical evidence that optical binding induces spatially localized vibrational modes in particle arrays, a mechanism distinct from traditional localization causes.

Findings

Optical binding can organize particles into stable 1D lattices.

Localized vibrational eigenmodes arise from long-range optical interactions.

Optical forces significantly influence the dynamics of particle arrays.

Abstract

We show, through analytical theory and rigorous numerical calculations, that optical binding can organize a collection of particles into stable one-dimensional lattice. This lattice, as well as other optically-bound structures, are shown to exhibit spatially localized vibrational eigenmodes. The origin of localization here is distinct from the usual mechanisms such as disorder, defect, or nonlinearity, but is a consequence of the long-ranged nature of optical binding. For an array of particles trapped by an interference pattern, the stable configuration is often dictated by the external light source, but our calculation revealed that inter-particle optical binding forces can have a profound influence on the dynamics.