Optical Trapping Forces from Electric Fields Inside Dielectric Materials

We developed a method for computing forces from internal electric fields. The internal fields are found using discrete dipole approximation (DDA) and finite difference time domain (FDTD) approaches and the results are compared. We are interested in the results from an optical trapping viewpoint, though other simulations are used for benchmarks. This method can handle arbitrary input beams and particle sizes and shapes. We hope to report on similar calculations to calculate optical torques on birefringent particles in the Mie size regime.