Temporal, spectral, and modal analysis of a thin-slab Tm:LuLF hybrid stable-unstable laser

Temporal instabilities observed in a thin-slab Tm:LuLF hybrid stable-unstable resonator are studied both experimentally and with numerical modelling. Near-field beam profiles and intra-cavity modes are investigated under different alignment conditions, and a two-dimensional Fox and Li model is developed and applied to verify the results. Laser rate equations for the gain medium can be integrated into the model to understand how Thulium’s complex energy structure may be influencing the resonator dynamics. The laser was scaled to ~30 W of high-brightness output power.