Tuning the Stiffness Asymmetry of Optical Tweezers via Polarization Control

TL;DR

This paper investigates how polarization control can be used to tune the asymmetry in trap stiffness of optical tweezers, enabling precise manipulation of the optical potential landscape for dielectric spheres larger than the wavelength.

Contribution

It introduces a method to control trap stiffness asymmetry in optical tweezers through polarization, even with strongly focused fields and larger dielectric particles.

Findings

Polarization significantly influences trap stiffness asymmetry.

Tuning polarization allows customization of the optical potential landscape.

The method is effective for dielectric spheres larger than the wavelength.

Abstract

Optical tweezers that utilize a highly focused, linearly polarized laser beam exhibit strong trap stiffness asymmetry, which originates from the anisotropic field distribution in the transverse plane. Based on the previous study of polarization-dependent focused field distribution, we explore its manifestation in optical trap in terms of trap stiffness asymmetry. Our results demonstrate that polarization control provides a versatile tuning knob for tailoring optical potential landscape even in case of a strongly modified focused field in the presence of dielectric spheres larger than the wavelength of a trap beam.