Optical forces for many particle systems in complex beams

A long standing problem with computational modelling of optical forces via the discrete dipole approximation (DDA) lies in the inaccessibility of many particle systems due to the rapid growth in complexity with both system size, P, and particle fidelity, N. In this presentation we will demonstrate how thanks to advances in computing power, we have created a discrete dipole approximation (DDA) program which allows the modelling of optical forces for particle systems with both many dipoles and many particles. By augmenting this program with a bespoke beams library and feeding into a hydrodynamic model, we can achieve simulations of many particles in complex beams such as Bessel, complex source point, Gaussian and Laguerre-Gaussian, as well as evanescent fields. To demonstrate this work, we first briefly explore DDA and verify our final scaling of O(P²NlogN), before moving on to explore the dynamics of systems with tens to hundreds of particles, each in turn comprising thousands of dipoles, in a variety of incident beams. Finally, we touch upon more complex methods of calculating both rotations and hydrodynamics that would allow for many particle modelling of arbitrary 3D particles.