Adaptive compensator of thermally induced lens with analyzer based on quadrant photodiode

We used a quadrant photodiode as a sensor of wavefront curvature in the compensator of thermally induced lens and wedge in laser rods. Sensitivity of the wavefrontcurvature analyzer λ/100 was achieved. Using of thermal lens compensator with such sensor provided output beam divergence <;1.5×DL in 100ps 0.5J×200Hz Nd:YAG laser.