Collective scattering and oscillation modes of optically bound point particles trapped in a single mode waveguide field

TL;DR

This paper investigates the collective oscillation modes of particles trapped in an optical waveguide, revealing complex eigenmodes, instabilities, and the impact of multiple scattering and absorption on these self-organized structures.

Contribution

It provides a detailed analysis of the collective excitations and instabilities in optically bound particle arrays within a waveguide, highlighting the effects of multiple scattering and absorption.

Findings

Eigenmodes are complex and depend on particle number and pump strength.

Multiple scattering and absorption significantly alter eigenfrequencies.

Larger arrays tend to become dynamically unstable and disintegrate.

Abstract

Collective coherent scattering of laser light induces strong light forces between polarizable point particles. These dipole forces are strongly enhanced in magnitude and distance within the field of an optical waveguide so that at low temperature the particles self-order in strongly bound regular patterns. The stationary configurations typically exhibit super-radiant scattering with strong particle and light confinement. Here we study collective excitations of such self-consistent crystalline particle-light structures as function of particle number and pump strength. Multiple scattering and absorption modify the collective particle-field eigenfrequencies and create eigenmodes of surprisingly complex nature. For larger arrays this often leads to dynamical instabilities and disintegration of the structures even if additional damping is present.