<title>Patterns and weak optical turbulence in wide-aperture lasers</title>

Abstract

Complex pattern formation is commonly observed in spatially extended, continuous, dissipativesystems which are driven far from equilibrium by an external stress. Under the influence of thisstress, the system can undergo a series of symmetry breaking bifurcations or phase transitions andthe resulting patterns become more and more complicated, both temporally and spatially, as thestress is increased. Examples abound in ordinary and binary fluids, in liquid crystals and chemicallyreacting media1. Optical systems, both passive and active, are no exception and considerable efforthas been expended recently to predict2'3 and observe4'5 pattern forming instabilities in both passiveand active nonlinear optical systems.Wide aperture gas and semiconductor lasers offer the possibility of producing high power stablecoherent outputs ranging from tens of watts to kilowatts and possibly higher. These lasers also pro-vide ideal physical scenarios for the observation of spatio-temporal complexity in spatially extendeddissipative systems.