# Omnidirectional Transport in Fully Reconfigurable Two Dimensional Optical Ratchets

## TL;DR

This paper introduces a reconfigurable 2D optical ratchet system that enables controlled directed transport of particles in multiple directions, highlighting the role of asymmetry over driving orientation.

## Contribution

We present a novel holographic optical micromanipulation system capable of creating arbitrary 2D lattice potentials with tunable asymmetry for particle transport studies.

## Key findings

- Directed transport occurs in multiple directions, including on-axis, perpendicular, and oblique.
- Transport direction is primarily determined by potential asymmetry, not driving orientation.
- The system reveals additional symmetry-breaking effects due to lattice configuration.

## Abstract

A fully reconfigurable two-dimensional (2D) rocking ratchet system created with holographic optical micromanipulation is presented. We can generate optical potentials with the geometry of any Bravais lattice in 2D and introduce a spatial asymmetry with arbitrary orientation. Nontrivial directed transport of Brownian particles along different directions is demonstrated numerically and experimentally, including on-axis, perpendicular and oblique with respect to an unbiased ac driving. The most important aspect to define the current direction is shown to be the asymmetry and not the driving orientation, and yet we show a system in which the asymmetry orientation of each potential well does not coincide with the transport direction, suggesting an additional symmetry breaking as a result of a coupling with the lattice configuration. Our experimental device, due to its versatility, opens up a new range of possibilities in the study of nonequilibrium dynamics at the microscopic level.