Laser polarization dynamics, control, synchronization and noise effects

A quasi - isotropic CO2 laser close to resonance can present polarization bistability, with spontaneous jumps between two orthogonal linear states. We explore the potential applications of this bistable dynamics showing that polarization can be controlled by means of a suitable optical feedback. In this way, information can be encoded in the polarization process and it can be safely recovered at an identical laser receiver synchronized with the sender. As white noise is added to the switching process other constructive effects like coherence resonance and stochastic resonance have been found.