# Mechanism of the ordered particles arrangement in a concentration grating excited in the field of counter-propagating Gaussian beams

## TL;DR

This paper investigates how small transparent particles arrange themselves in a concentration grating created by counter-propagating Gaussian laser beams, focusing on the combined effects of gradient and Coulomb forces.

## Contribution

It introduces a two-particle approximation model explaining the ordered particle arrangement due to gradient and Coulomb forces in laser-induced concentration gratings.

## Key findings

- Particles form ordered structures under specific laser conditions
- Dipole-dipole interactions significantly influence particle arrangement
- The model explains experimental observations of particle patterns

## Abstract

In the two-particle approximation, we consider the mechanism for the formation of an ordered arrangement of transparent spherical particles of small size in a concentration grating excited by the gradient force of counter-propagating Gaussian laser beams. This mechanism is due to the joint action of the transverse gradient force and the Coulomb force arising as a result of dipole-dipole interactions between particles.