Enhancement of the TEM00power in Nd:YAG and Nd:YAlO3lasers

Attempts to obtain large TEM00mode powers from CW-operated Nd: YAG lasers have generally been unsuccessful due to depolarization and phasefront distortion resulting from thermally induced nonuniform optical anisotropy in the active material. Several methods have been proposed to neutralize the anistropy´s detrimental effects. These techniques involve either birefringence compensation or the use of a new host material (yttrium ortho-aluminate) for the active Nd-ions. YAlO3has a strong natural uniform birefringence which is only weakly perturbed by the thermal component.