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.

Recent Progress in Nonlinear Frequency Conversion of Optical Vortex Lasers

“…In 2021, they realized a tunable topological charge as high as 18th with an axicon [48]. Off-axis pumping [49][50][51][52][53][54][55] is to achieve the asymmetric pumping condition, which can efficiently hinder the oscillation of low-order modes. It is realized mainly by tilting the crystal or shifting the position of the pump spot on the crystal.…”

Advances of Yb:CALGO Laser Crystals

“…An alternative vortex beam generator was also demonstrated with a mirror curvature dynamically controlled Z-shaped resonator in Figure 3c [85]. Researchers also found that by rotating the Yb:CALGO crystal in the cavity, vortex arrays could be produced directly as well [86]. Another interesting structured beam is the conical refraction (CR) light, i.e., a hollow cylinder light with annular intensity profile after the beam propagates conically through a laser crystal [87].…”

Broadband 2D n × n Vortex Arrays Generated from an Efficient Petal‐Like Raman Laser with an Astigmatic Mode Convertor

“…[28,29] Optical vortex arrays were obtained in a Yb:CALGO laser by rotating crystal to break cavity symmetry. [30] Optical vortex arrays were directly generated in a Yb 3+ :Y 3 AL 5 O 12 (Yb:YAG) microchip laser under tilted annular beam pumping. [31] 1D optical vortex arrays with tunable singularities and high peak power have been generated in a passively Q-switched microchip laser pumped with a decentered annular beam.…”