Figure 4.

(a) Operational scheme used to shift the dynamical properties in liquid, employing a photothermal actuation at the oscillator base. An optical beam deflection scheme employs a red laser to measure the oscillator deflecting angle. The PID loop keeps the cantilever deflecting angle constant by driving the power of the blue laser focused at the oscillator base. (b) Frequency response of the NMO in water for different control parameters. The dashed curve presents the unperturbed response, while the remaining experiments are done keeping the Q-control/derivative gain constant, and applying a negative (green) and positive (red) or null (blue) Proportional gain.