Discrete dipole approximation

Summary

The discrete dipole approximation is a numerical method for the scattering of light by a particle of arbitrary shape. The particle is replaced by a finite array of polarizable points, each of which becomes an oscillating dipole. Each dipole responds to the incident field plus the fields of all other dipoles, which gives a linear system for the dipole moments. It is widely used for dust grains, ice crystals and nanoparticles whose shape is too irregular for exact series solutions. See the definition.