The adoption of a statistical mechanical framework in optics provides realistic models for multimode laser systems, whose experimental implications are presented and critically analyzed. A model for passive mode locking lasers is analyzed beyond the mean-field approxi- mation, accounting for the presence of many well-resolved frequencies of the lasing modes. The inhomogeneous structure in the nonlinear “mode locked” interaction network is shown to yield short pulses and phase waves with nontrivial slopes, corresponding to a phase delay of the pulsed laser signal. The analytic solution of a mean field-model for multimode laser in open and irreg- ular cavities will be, afterwards, addressed. The complete phase diagram, in terms of degree of disorder, pumping rate of the source and strength of nonlinearity, consists of four different pho- tonic regimes: incoherent fluorescence, mode locking, random lasing and the novel “phase locking wave”. A replica symmetry breaking transition occurs at the random lasing threshold. For a high enough strength of nonlinearity, a whole region with nonvanishing complexity anticipates the transition and the light in the disordered medium displays typical glassy behavior.