Simulating elastic light scattering using high performance computing methods

The Coupled Dipole method, as originally formulated byPurcell and Pennypacker, is a very powerful method tosimulate the Elastic Light Scattering from arbitraryparticles. This method, which is a particle simulationmodel for Computational Electromagnetics, has one majordrawback: if the size of the particles grows, or if scatteringfrom an ensemble of randomly oriented particles has to besimulated, the computational demands of the CoupledDipole method soon become too high. In this paper wepresent two computational techniques to resolve thisproblem. First we have implemented the Coupled Dipolemethod on a Massively Parallel Computer. The parallelefficiency can be very close to one, implying that attainedcomputational speed scales perfectly with the number ofprocessors. Secondly we propose to reduce thecomputational complexity of the Coupled Dipole methodby including ideas from the so-called fast multipolemethods (hierarchical algorithms) into the Coupled Dipolemodels. In this way the calculation time can be decreasedwith orders of magnitude.