Modeling the propagation of apertured high-order Laguerre-Gaussian beams by a user-friendly version of the mode expansion method

International audienceThe mode expansion method (MEM) models the propagation of an apertured beam by expressing the diffracted field as a finite series of Laguerre–Gaussian or Hermite–Gaussian modes. An optimal expansion parameter set (beam waist of the modes and its location) reduces the number of modes, which is difficult to derive, especially for high-order incident beams. We propose a user-friendly version of the MEM in which the expansion parameter set and the suitable number of modes are simply deduced from the approximation of the apertured incident beam