Experimental study of a VBG-based Tm:YLF slab laser at different output coupler parameters

摘要

The performance of a Tm:YLF slab laser is studied at different output coupler parameters. Use is made of a 20-mm-long a-cut slab crystal doped with 2.5 at. % thulium ions. With a volume Bragg grating and a Fabry-Perot etalon, the selected output wavelength of this Tm: YLF slab laser is 1908 nm. For the optimised output coupler with a transmission of 20% and a radius of curvature of 300 mm, the output power exceeds 74.1 W and the slope efficiency with respect to the absorbed pump power reaches 48.4%. In addition, the beam quality of the Tm:YLF slab laser is improved.