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Updated: Jun 22, 2026

Direct Force Measurements of Subcellular Mechanics in Confinement using Optical Tweezers
Published on: August 31, 2021
Measurement of the total optical angular momentum transfer in optical tweezers
Abstract:
We describe a way to determine the total angular momentum, both spin and orbital, transferred to a particle trapped in optical tweezers. As an example an LG(02) mode of a laser beam with varying degrees of circular polarisation is used to trap and rotate an elongated particle with a well defined geometry. The method successfully estimates the total optical torque applied to the particle. For this technique, there is no need to measure the viscous drag on the particle, as it is an optical measurement. Therefore, knowledge of the particle's size and shape, as well as the fluid's viscosity, is not required.
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