  Stochastic resonance is a general phenomenon usually observed in
one-dimensional, amplitude modulated, bistable systems.We show experimentally
the emergence of phase stochastic resonance in the bidimensional response of a
forced nano-electromechanical membrane by evidencing the enhancement of a weak
phase modulated signal thanks to the addition of phase noise. Based on a
general forced Duffing oscillator model, we demonstrate experimentally and
theoretically that phase noise acts multiplicatively inducing important
physical consequences. These results may open interesting prospects for phase
noise metrology or coherent signal transmission applications in nanomechanical
oscillators. Moreover, our approach, due to its general character, may apply to
various systems.
