Analysis and detection of spatial coherence and frequency-locking in multi-mode lasers

This paper focuses on techniques to study the nature of multi-mode laser dynamics that are based on an appropriate entropy and recently developed in the context of multi-mode laser dynamics. Result reveals that the complexity of the laser dynamics is not necessarily a monotonic function of the pump power for lasers with a two-level active medium. On the contrary, it is possible for the complexity first to increase and then to decrease as a function of the pump power. From a practical point of view, the key point is that the spatial coherence of the laser beam improves when its complexity decreases.