Fast far-field calculation in the discrete dipole approximation

•We have dramatically accelerated the computation of scattered far-field in DDA.•We use Fast Fourier Transforms to compute far-field in DDA.•Efficient computation of differential cross-section with DDA.

The discrete dipole approximation is an efficient technique for simulating the field radiated by a particle of any shape. In this approach, the object is viewed as a collection of radiating electric dipoles. The field scattered by the particle is obtained by summing the fields radiated by each dipole. When the particle size is much larger than the wavelength, this technique is time consuming. We propose a Fourier based method which permits a significant reduction of the computation time.