GENERATION AND PROPAGATION OF LAGUERRE-GAUSSIAN BEAMS
In this paper, we numerically study the propagation of classical Laguerre-Gaussian (LG) beams and three-index LG beams. The LG modes are the higher-order modes in contrast the Gaussian modes, which are the fundamental modes and have simpler intensity profile. We get the intensity and the phase distribution of the beams to visualize their structure during propagation. The propagation of beams in free space is modeled using the Fresnel transform, and the input field image distribution in the rear focal plane of the lens is modeled using the Fourier transform. The results proved that the standard LG beams preserve their structure up to a scale. Three-index LG beam structure was studied as well.