High-power master-oscillator power-amplifier with optical vortex output

Abstract

A high-power master-oscillator power-amplifier with optical vortex output is reported. The master oscillator for an optical vortex seed beam is a simple two-mirror Nd:YAG laser using a fiber-based pump beam conditioning scheme. The seed is amplified in a double-clad multimode fiber amplifier end-pumped by a high-power diode laser at 975 nm yielding 10.7 W of continuous-wave output at 1064 nm in the first-order Laguerre-Gaussian beam with M (2) a parts per thousand 2.11 for an absorbed pump power of 17.5 W, corresponding to a slope efficiency of similar to 59 %. The ring-shaped intensity profile and the wave front handedness of the seed beam were well preserved in the fiber amplifier. The prospects of power scaling via this approach are discussed.