Entropy and Correlation Time in a Multimode Dye Laser
In a recent paper the results of an experimental study of a multimode cw dye laser were reported. It was found that above a certain pumping level the intensities of the cavity modes became unstable and began to fluctuate nonperiodically. From time series of mode intensities the intensity correlation time τ c and order-2 Kolmogorov entropy K2 were determined. The correlation time was defined as the width of the peak of the monotonically decreasing autocorrelation function of intensity, and was found to decrease with increasing pump level. This can be understood by arguments based on coherent mode coupling. The entropy was determined using the algorithm of Grassberger and Proccacia, and was found to increase with increasing pump level.