Direct generation of optical vortex arrays by rotating in an all-solid-state Yb:CALGO laser

Abstract

We report the direct generation of optical vortex arrays in a diode-pumped bulk Yb:CALGO laser. By adjusting the angles of the input mirror, output coupler and laser crystal to achieve off-axis-pumped condition, the ring-shaped LG0,±1, two to six order vortex array have been obtained. The phase singularities of optical vortex arrays were tunable from 1 to 6. When the pump power was 13.41 W, the maximum output power of LG0,±1, double-vortex array, three-vortex array and four-vortex array were 1.93 W, 1.5 W, 1.02 W and 0.79 W respectively. The chirality could be adjusted by rotating the output coupler. The topological charges of each phase singularity were determined by interference pattern. Theoretical simulation including intensity distribution, interference fringes and phase distribution have been analyzed. The simulations are in good accordance with experimental results.