Thermal Distortion Compensation And Resonator Design Of Disk Laser Based On Diffractive Phase Elements

With the development of the technology of thin disk laser, the issues of solid state laser thermal lensing effect have been drastically reduced. Currently, research has focused on the fundamental mode operation of disk laser in order to ensure good beam quality. However, due to limitations of cooling capacity, the thermal distortion of disk is still inevitable in high output powers disk laser. The wavefront deformations introduced by thermal distortion of disk directly lead to additional diffractive losses, resulting in severe efficiency and beam quality reductions. The wavefront deformations can be corrected by designing an appropriate diffractive phase elements in the resonator mirrors. The negative effects caused by thermal distortion could decline or even disappear for the improvement of efficiency and beam quality. For further research, by designing diffractive phase elements on resonator mirrors, the distribution of the fundamental mode optical field can also be controlled as desired.In this thesis, the thermal distortion is decomposed into spherical part and aspherical part, then analyzing the impact caused by spherical and aspherical thermal distortion respectively on fundamental mode optical field. Compared to the spherical distortion, the impact of aspherical distortion is much more severe on fundamental mode optical field. Three methods based on diffractive phase elements are put forward to compensate the wavefront deformations of the fundamental mode optical field introduced by aspherical thermal distortion of disk. Find the optimal one by comparing these methods. In next analysis, we achieve a special disk laser resonator mirror with diffractive phase elements for desired distribution of fundamental mode optical field. Finally, evaluate beam quality with M~2, consisting of all orders of standard Laguerre-Gauss optical fields.