Mean relaxation time approximation for dynamical correlation functions in stochastic systems near instabilities - II. The single mode laser

Correlation functions for the stochastic description of the single mode laser are investigated using the simple approximation method presented in part I[1]. The application of the mean relaxation time approximation to stochastic systems with state spaces of dimension d>1 is thereby demonstrated. Our approach yields results which are indistinguishable from the actual lineshape. Hence, they constitute a slight improvement over the results of Risken and co-workers, where these results are based on an analysis of the lowest eigenvalue of the stochastic operator.