Eur. Phys. J. B 69, 93-100 (2009)
https://doi.org/10.1140/epjb/e2009-00099-1

Stochastic and coherence resonance in lasers: homoclinic chaos and polarization bistability

¹ CNR Instituto Nazionale di Ottica Applicata, Largo E. Fermi 6, 50125 Firenze, Italy
² Dept. of Physics, University of Firenze, Firenze, Italy

Corresponding author: ^a tito.arecchi@inoa.it

Received: 26 January 2009
Revised: 13 February 2009
Published online: 18 March 2009

Abstract

We report Stochastic Resonance and Coherence Resonance phenomena in experiments using CO₂ lasers. First, we consider a polarized laser with feedback; for suitable feedback parameters, the laser intensity undergoes homoclinic chaos consisting in the return to a saddle focus, where noise controls the permanence time around the saddle. Second, we discuss a quasi-isotropic laser where noise induces switching between two intensity components with mutually orthogonal polarization.