Direct generation of high-power femtosecond Laguerre–Gaussian and Bessel vortex beams in a thin-disk laser oscillator

Abstract Ultrafast vortex beams are essential in many scientific and industrial fields owing to their unique spatial and temporal characteristics. We demonstrate a passively mode-locked ytterbium-doped yttrium aluminum garnet (Yb:YAG) thin-disk oscillator that directly generates high-power femtosecond vortex beams with excellent beam quality. Using Kerr-lens mode-locking assisted by a semiconductor saturable absorber mirror, we achieve 594 fs Laguerre–Gaussian vortex pulses with 50 W average power at a 68.5 MHz repetition rate, representing the highest power reported for a femtosecond vortex oscillator. By replacing the planar output coupler with a coated axicon, we further realize stable mode-locking and efficient generation of first-order Bessel vortex beams. This compact and integrated design eliminates external mode converters, enabling robust generation of high-power ultrafast structured light. The demonstrated source provides a promising platform for precision material processing, strong-field vortex dynamics and quantum optical studies.