Unstable resonator beam stability in planar waveguide Nd:YAG lasers

Planar waveguide solid-state lasers based on Nd:YAG or Yb:YAG and pumped by diode lasers offer excellent prospects for scaling to extremely high power from very compact structures. They also offer fast warm up and rapid stabilisation of the beam through their low thermal mass and effective cooling. This work has shown that laser operation with large waveguide core size, up to ∼250 μm, can remain free of thermal lens effects in the direction transverse to the waveguide plane to much higher powers. Current research aims to maintain the beam quality and improve pointing stability at higher powers from the edge-coupled unstable resonator that is used in the free-space, lateral direction.