Calculating optical forces with skew line ray model for Gaussian beam

Shuhe Zhang, Meng Shao, Xiao Yang, Jinhua Zhou

Ray optics models in optical tweezers are confined to two specific cases: ray pencil model for a highly focused beam and spherical wave front model for a weakly focused beam. In this manuscript, the skew lines of one sheet hyperboloid are introduced as rays’ trajectories to trace the propagation of a Gaussian beam for calculating optical forces. The simulations of trapping efficiencies demonstrate the skew-line ray model is valid in comparison with traditional ray-optics models including spherical wave front model and ray pencil model. Our results of transverse and axial trapping efficiencies show that the skew-line ray model has good performances in both highly and weakly focused beams. Furthermore, the influence of the spherical aberration is discussed, and our results are accordance with that from traditional ray-optics models. The SLR method unifies ray pencil model and spherical wave front model into one way, and can be used to calculate optical forces in either paraxial or nonparaxial conditions. Thus, this model is more appropriate in extensive simulations in ray optics regime.

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