Intracavity control of a 200-W continuous-wave Nd : YAG laser by a micromachined deformable mirror

A silicon micromachined membrane deformable mirror with a diameter of 10 mm , reflectivity of better than 99.8%, and a surface deflection range of 3 mu m has been used for intracavity control of an industrial 200-W cw Nd:YAG la ser. When it was placed in the resonator, the mirror demonstrated continuou s (more than 40-h) stable operation under an similar to 550-W cw optical lo ad, with beam diameters in the range 3-6 mm. Periodic modulation of the cur vature of the deformable mirror with a frequency of 250 Hz produced quick s witching between stable and unstable resonator configurations, which result ed in pulse-period Q-switched generation with average power in the range 50 -200 W, modulation depth from 95% to 10%, and an M-2 parameter of 6.5 to 30 . (C) 2001 Optical Society of America.