We demonstrate the actuation of a double beam opto-mechanical cavity with a
sinusoidally varying optical input power. We observe the driven mechanical
motion with only 200 nW coupled to the optical cavity mode. We also investigate
the pump power dependence of the radio-frequency response for both the driving
power and the probe power. Finally, we investigate the dependence of the
amplitude of the mechanical motion on mechanical cavity quality factor.Comment: 11 pages, 6 figure