Noise Squeezing in a Nanomechanical Duffing Resonator

We study mechanical amplification and noise squeezing in a nonlinear nanomechanical resonator driven by an intense pump near its dynamical bifurcation point, namely, the onset of Duffing bistability. Phase sensitive amplification is achieved by a homodyne detection scheme, where the displacement detector's output, which has correlated spectrum around the pump frequency, is down converted by mixing with a local oscillator operating at the pump frequency with an adjustable phase. The down converted signal at the mixer's output could be either amplified or deamplified, yielding noise squeezing, depending on the local oscillator phase.