Q-factor control of a microcantilever by mechanical sideband excitation

We demonstrate the coupling between the fundamental and second flexural mode of a microcantilever. A mechanical analogue of cavity-optomechanics is then employed, where the mechanical cavity is formed by the second vibrational mode of the same cantilever, coupled to the fundamental mode via the geometric nonlinearity. By exciting the cantilever at the sum and difference frequencies between fundamental and second flexural mode, the motion of the fundamental mode of the cantilever is amplified and damped. This concept makes it possible to enhance or suppress the Q-factor over a wide range.