Thermooptic distortions and large-scale self-focusing in active elements of highpower laser systems

Mechanisms of thermooptic distortions in active elements, which are important in the case of athermal glasses, are investigated theoretically for the first time. Detailed studies are made of the deformation of the end surfaces of active elements of rectangular and circular cross sections subject to an allowance for the specific pumping conditions near the ends. A numerical modeling allowing for thermooptic distortions and large-scale focusing is reported: it reveals characteristics of the divergence of high-power laser radiation in an amplifier with an active element of rectangular cross section.