FARADAY INSTABILITY IN A MULTIMODE LASER

We show theoretically and experimentally that a basic pattern formatio n mechanism in hydrodynamics, the Faraday instability, can be observed in optics (for modulated class B lasers with inhomogeneous broadening ). As for the Faraday problem, stationary waves are excited parametric ally and wave numbers are selected by the dispersion curve of the medi um. The mechanism is evidenced by a multiple-scale analysis of the phy sical laser model, and is confirmed experimentally using a Nd-doped fi ber laser.