  We explain optical and mirrors displacement bistability in a hybrid
optomechanical system in the presence of a strong laser driving field and a
weak probe field. External modulating fields are applied selectively on movable
mirrors. We show that the optomechanical coupling, electromechanical Coulomb
coupling and, amplitude & phase of external modulating fields are important
parameters to control the optical and mirror displacement bistable behaviour.
The parameters values are taken according to presently available experiments.
The study may be applied to the realization of a tunable electro opto
mechanical switch depending on the optomechanical and Coulomb coupling,
frequencies, threshold power, and the amplitude and phase of external
mechanical pumps.
