Strong thermo-optical aberrations in flash–lamp-pumped Nd:Cr:GSGG rods were corrected to yield TEM<sub>00</sub> output at twice the efficiency of Nd:YAG. A hemispherical resonator operating at the limit of stability was employed. As much as 3 W of average power in a Gaussian beam (<i>M</i><sup>2</sup> ≈1) was generated. Unique features were zero warm-up time and the ability to vary the repetition rate without varying energy, near- and far-field profiles, or polarization purity. Thermal focusing and astigmatism were corrected with a microprocessor-controlled adaptive-optics backmirror composed of discrete elements (variable-radius mirror). A reentrant resonator coupled polarizer losses back into the laser rod and corrected depolarization.
© 1998 Optical Society of America
(010.1080) Atmospheric and oceanic optics : Active or adaptive optics
(140.3380) Lasers and laser optics : Laser materials
(140.3410) Lasers and laser optics : Laser resonators
(140.6810) Lasers and laser optics : Thermal effects
(260.1440) Physical optics : Birefringence
Inon Moshe, Steven Jackel, and Raphael Lallouz, "Working Beyond the Static Limits of Laser Stability by Use of Adaptive and Polarization-Conjugation Optics," Appl. Opt. 37, 6415-6420 (1998)