On the possibility of high-frequency modulation of laser radiation by using a deformable mirror

The results of experimental studies of a cooled deformable mirror with a controllable curvature of the reflecting surface in the frequency range from 0 to 40 kHz are presented. The original method is used for measuring the amplitude- and phase-frequency characteristics of the mirror. The dependences of the reflecting surface deformation on the control voltage are obtained at different fixed frequencies near resonances. It is found that the nonlinearity of these dependences is caused by the shift of the resonance frequencies of the mirror with increasing the control voltage amplitude. The parameters of the mirror such as the linewidth, Q and damping factors, and peak sensitivity are studied at the 4.69-kHz fundamental and 37.2-KHz high-frequency resonances. It is found that upon the shift of resonance frequencies, the mirror Q factor and its peak sensitivity are independent of the control voltage amplitude. The high-frequency modulation depth of laser radiation that can be obtained with such intracavity mirrors is estimated from the results obtained.