Thin-disk laser scaling limit due to thermal-lens induced misalignment   instability
  We present an obstacle in power scaling of thin-disk lasers related with self-driven growth of misalignment due to thermal lens effects. This self-driven growth arises from the changes of the optical phase difference at the disk caused by the excursion of the laser eigen-mode from the optical axis. We found a criterion based on a simplified model of this phenomenon which can be applied to design laser resonators insensitive to this effect. Moreover, we propose several resonator architectures which are not affected by this effect. 
Karsten Schuhmann, Klaus Kirch, Francois Nez, Randolf Pohl, Aldo   Antognini
physics.optics