Focusing of different beams by short focus optics

In this paper, numerical methods for fast simulation of nonparaxial beam propagation are discussed. For small distances, in the near field or presence of focusing and other optical elements with high numerical aperture have to be used FFT-algorithms or calculation by rigorous expressions, e.g. eigenfunctions expansions. For long distances more effective is algorithm of correction in the space domain. In all cases of nonparaxial beam propagation when the far field distribution isn't limited to a half space, only rigorous solutions of the wave equation are valid.