ABSTRACT
In 1992 it was shown by Allen that the Laguerre-Gaussian (LG) modes have an orbital angular momentum (OAM). The OAM is also characteristic of all optical vortices or singular laser beams with a phase singularity or wavefront dislocation. The power flux (Poynting vector) of such beams rotates in a spiral about phase singularity points. In 1991, the conversion of a higher-order Hermite-Gaussian (HG) mode into a LG mode with phase singularity using an astigmatic mode converter was reported by Volostnikov. The laser beams with the OAM have found use in particle micromanipulation, quantum telecommunications, microscopy, interferometry, metrology, and so on. A most recent review of the OAM phenomenon can be found. This chapter demonstrates that it is possible to obtain a light field with an arbitrary integer OAM through the interference of just two HG modes with definite indices. It analyzes generalized HG beams, which change to the HG modes and elegant HG beams under certain parameters.
