Modelling Optomechanical Responses in Optical Tweezers Beyond Paraxial Limits

TL;DR

This paper presents a numerical method to accurately model optomechanical responses of dielectric nanoparticles in optical tweezers beyond paraxial approximations, enabling precise characterization for levitodynamics applications.

Contribution

The authors develop a 3D numerical simulation approach to predict optical tweezer responses with high fidelity, surpassing traditional paraxial models.

Findings

Validated method by measuring oscillation frequencies

Achieved high-accuracy predictions of optomechanical parameters

Applicable to diverse dielectric particles in levitodynamics

Abstract

Optically levitated dielectric nanoparticles have become valuable tools for precision sensing and quantum optomechanical experiments. To predict the dynamic properties of a particle trapped in an optical tweezer with high fidelity, a tool is needed to compute the particle's response to the given optical field accurately. Here, we utilise a numerical solution of the three-dimensional trapping light to accurately simulate optical tweezers and predict key optomechanical parameters. By controlling the numerical aperture and measuring the the particle's oscillation frequencies in the trap, we validate the accuracy of our method. We foresee broad applications of this method in the field of levitodynamics, where precise characterisation of optical tweezers is essential for estimating parameters ranging from motional frequencies to scattering responses of the particle with various dielectric properties.