A T-matrix approach for particles with small-scale surface roughness

Abstract

We combine group theory with a perturbation approach to perform T-matrix computations for particles with small-scale surface roughness up to size parameters of 70. The optical properties of high-order 3D-Chebyshev particles differ substantially from those of spheres. CPU times are reduced by more than 4-5 orders of magnitude by the use of group theory, while the perturbation approach circumvents the notorious ill-conditioning problems of the null-field method, thus allowing the treatment of large size parameters.