Numerical simulation of the physical properties of Gaussian mode using the angular spectrum technique

This research aims to study the analytical and numerical simulation of the Gaussian beams variables of the fundamental mode TEM00 during its propagation in free space between two parallel planes, using the angular spectrum technique. A dedicated computational program in Borland C++ Builder was developed to calculate the diffraction through the angular spectrum technique with the application of two fast 2D Fourier transforms. Some 2D and 3D cross-sections of results are presented. That helped to present the complex amplitude of the Gaussian beams with its real and imaginary parts, Gouy phase shift and full phase and intensity distribution. The Gaussian beam is one of the rare cases when the diffraction problem solution, defined within the frames of scalar and paraxial approximation, is given in the exact analytical form. A comparison between that form and the results of the angular spectrum algorithm brings information about the performance quality of that algorithm.