Research on direct generation of high-power and high-order vortex lasers using defect-mirror technology (Invited)

Vortex light has important applications in optical communication, quantum entanglement, new nonlinear optical effect, micro- and nano-mechanical processing, super-resolution imaging and optical tweezers, etc. The precondition of vortex light applications is the generation of high-quality vortex light. The method of spot defect mirror combined with solid-state laser technology has outstanding advantage in direct generation of high-order vortex light with high quality and high stability. At present, this method has mostly used in various two-mirror linear cavities for laser generation in continuous-wave mode. A spot defect mirror using an ultraviolet picosecond laser was fabricated. Then, an diode-end-pumped Nd:YVO₄ laser with a V-shaped laser cavity configuration was arranged. Based on this laser, a 2.69 W vortex laser with topological charge of 3 was achieved. Slope efficiency of this 3^rd vortex laser was about 23.6%. Further changing the cavity length and defect spot size, high-order vortex laser output with topological charges up to 11 and 13 was also achieved. This research clearly indicates that the spot defect mirror technology can directly generate high-order vortex laser in a structurally complicated laser resonator, which has provided reference for Q-switched and/or mode-locked high-order vortex laser generation.