  Stochastic resonance with white noise has been well established as a
potential signal amplification mechanism in nanomechanical two-state systems.
While white noise represents the archetypal stimulus for stochastic resonance,
typical operating environments for nanomechanical devices often contain
different classes of noise, particularly colored noise with a 1/f spectrum. As
a result, improved understanding of the effects of noise color will be helpful
in maximizing device performance. Here we report measurements of stochastic
resonance in a silicon nanomechanical resonator using 1/f noise and
Ornstein-Uhlenbeck noise types. Power spectral densities and residence time
distributions provide insight into asymmetry of the bistable amplitude states,
and the data sets suggest that 1/f^alpha noise spectra with increasing noise
color (i.e. alpha) may lead to increasing asymmetry in the system, reducing the
achievable amplification. Furthermore, we explore the effects of correlation
time tau on stochastic resonance with the use of exponentially correlated
noise. We find monotonic suppression of the spectral amplification as the
correlation time increases.
