Large-aperture Nd:glass laser amplifiers with high pulse repetition rate

Nd:glass amplifiers are used in most of the existed petawatt laser facilities. A typical repetition rate of such lasers is 1 shot per 30 minutes or less. Limitations are thermally induced distortions of radiation and tensile stresses in Nd:glass. An increase of the repetition rate is an urgent problem. We have investigated thermally induced depolarization and thermal lens effects in Nd:glass rods up to 10 cm in diameter at a pump pulse repetition period of 3 minutes. It is shown that the rods have a safety factor of at least 5 before thermal stress induced damage would occur, and despite of their size phase and polarization distortions could be compensated.