Rigorous Theory of Optical Trapping by an Optical Vortex Beam

TL;DR

This paper develops a rigorous theoretical framework for optical trapping using optical vortex beams, revealing complex force interactions and diverse particle dynamics influenced by damping, advancing understanding of mesoscopic particle manipulation.

Contribution

It introduces a comprehensive theory showing that optical vortex traps involve complex force constants and damping effects, challenging the traditional gradient force perspective.

Findings

Optical vortex traps can have complex force constants.

Particle dynamics vary with damping, including stable, periodic, and aperiodic motions.

Trapping stability depends on ambient damping levels.

Abstract

We propose a rigorous theory for the optical trapping by optical vortices, which is emerging as an important tool to trap mesoscopic particles. The common perception is that the trapping is solely due to the gradient force, and may be characterized by three real force constants. However, we show that the optical vortex trap can exhibit complex force constants, implying that the trapping must be stabilized by ambient damping. At different damping levels, particle shows remarkably different dynamics, such as stable trapping, periodic and aperiodic orbital motions.