Signal amplification in a nanomechanical Duffing resonator via   stochastic resonance
  We experimentally study stochastic resonance in a nonlinear bistable nanomechanical resonator. The device consists of a PdAu doubly clamped beam serving as a nanomechanical resonator excited capacitively by an adjacent gate electrode and its vibrations are detected optically. The resonator is tuned to its bistability region by an intense pump near a point of equal transition rates between its two metastable states. The pump is amplitude modulated, inducing modulation of the activation barrier between the states. When noise is added to the excitation, the resonator's displacement exhibits noise dependent amplification. We measure the resonator's response in the time and frequency domains, the spectral amplification and the statistical distribution of the jump time. 
Ronen Almog, Stav Zaitsev, Oleg Shtempluck and Eyal Buks