Research On Measurements Of The Thermo-optical Aberration Of A Thin Disk Laser Crystal Based On Spatial Fourier Analysis With A Three Surface Interferogram

Thermal effect and thermo-optical aberration limit high output power and high beam quality of thin-disk laser.To improve the beam quality of thin-disk laser,based on the precise measurements of thermo-aberration of thin disk laser crystal,the compensation by deformable mirrors are significant methods.However,lots of disturbance will influence the accuracy of the thermal distortion measurements,just as the vibration from the water-jet impingement cooling system,the multi-pass pumping scheme for thin disk laser consisting of dual parabolic mirrors with conjugated relationship and the three-surface interferogram.Therefore,besides the advantage of anti-vibration,we introduce the method based on spatial Fourier analysis with a three-surface interferogram.With this method,using a 532 nm laser as the light source of interferometer,we not only can get a much more precise result but also can conveniently build the experimental setup.The arrangements of this paper are as follows.In the 1st chapter,the progress of the measurements of thermo-aberration of thin disk laser are introduced.In the 2nd chapter,we give the introductions of how different interferometers work in the environment with vibrations.In the 3rd chapter,we take a deep research on the three-surface interference in a thin disk laser crystal.In the 4th chapter,we take this method into practice where we successfully measure the distribution of thermo-aberration of a thin disk laser crystal with the pumping power up to 493 W regardless of the vibration from environment.The repeatability of RMS is 1.153 nm.These results would be beneficial to the design of a stable resonator and to the compensation for thermo-aberration with intracavity deformable mirrors.