Thermally induced spherical aberration in high power diode pumped laser module

The method of spherical aberration measurement and compensation is introduced for the high power and high beam quality diode pumped Nd:YAG rod lasers. The S-H wavefront sensor is employed to measure the 3rd spherical aberration, and a compensator is designed to correct it. The overall aberrations with and without compensation are analyzed. The beam quality factor of a master-oscillator power-amplifier system is improved from 9.2 to 6.4 with spherical aberration compensation(SAC). The experiment results prove that the 3rd spherical aberration of laser rod can be eliminated by SAC without increasing other aberrations, thus improving the beam quality of lasers.