Generation of high-order coaxial and multi-axial Laguerre-Gaussian beams from degenerate laser cavities

We use a diode-pumped laser to generate the rectangular symmetric optical modes which comprise degenerate Hermite-Gaussian modes. By use of a mode converter, Hermite-Gaussian modes can be transformed into Laguerre-Gaussian modes possessing optical orbital angular momentum. Furthermore, we use a mode converter to transform the superposed Hermite-Gaussian modes into the superposed Laguerre-Gaussian modes which lead to high-order coaxial and multi-axial Laguerre-Gaussian beams. Experimental results show that the structured beams can be systematically generated from laser cavities and have good agreement with the theoretical analyses.