Tuning the Stiffness Asymmetry of Optical Tweezers via Polarization Control

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.