A planar waveguide Nd:YAG laser with a hybrid waveguide–unstable resonator

Abstract

Mode selection processes are presented for a 200 μm active thickness Nd:YAG planar waveguide laser, pumped by 10 laser diode bars in a multi-pass, slotted mirror pump chamber. A hybrid waveguide–unstable resonator is shown to be effective at mode control, producing a single, edge-coupled output beam of up to 5 W average power for quasi-CW pulsed pumping. A lateral M2 factor of 1.5 and a low order waveguide mode with a transverse M2 factor of 4.3 is obtained with 4 W output. The resonator configuration is shown to be unaffected by transverse or lateral thermal lens effects.