Direct generation of Laguerre-Gaussian modes in an all-solid-state laser

Abstract

By employing a hybrid scheme that combines annular pumping and off-axis pumping, this study achieves the direct generation of single-handed vortex beams from the laser resonator. The gain medium of the solid-state laser is subjected to annular end-pumping, while off-axis pumping is realized by tilting the output mirror. The adjustment of the gain medium’s longitudinal position ensures the matching of pump light to the Laguerre-Gaussian (LG0n) modes within the cavity. In the experiments, vortex lasers with LG01, LG02, and LG03 modes are successfully obtained at a pump power of 5.5 W. The corresponding maximum output powers are 0.75 W, 0.67 W, and 0.59 W, with optical conversion efficiencies of 13.6 %, 12.2 %, and 10.7 %, respectively. The handedness of the vortex beams is simply reversed by flipping the off-axis displacements. Numerical simulations are conducted to reconstruct the experimental results, employing the theory of coherent superposition of LG modes.