Transfer of Linear and Angular Momentum from Evanescent Fields of an Optical Fiber to Isotropic and Anisotropic Dipolar Spheres.

We calculate the force and torque on a transparent isotropic dipolar sphere due to the higher-order evanescent field modes propagating outside a few-mode optical fiber immersed in water. After applying these results to find the orbital trajectory and spin dynamics of an isotropic sphere, we then use perturbation theory to calculate the orbital trajectory of a weakly anisotropic sphere.