Abstract

The dynamic evolution of a multimode laser is a problem of considerable complexity because of the large number of variables and system parameters that may affect its behavior. The more simplified case of a two-mode system has, however, been a subject of considerable theoretical and experimental investigations. Of particular interest is the work of Shih and Milonni¹ who theoretically show that the presence of moderate inhomogeneity in the gain may lead to the breakdown of regular emission of a two-(transverse) mode homogeneously broadened laser into chaos through a period-doubling route. As discussed in this reference such a situation, namely, the spatial nonuniformity in gain, can be achieved in gas lasers where electron distribution in the electrical discharge is not necessarily truly homogeneous. Here we report on the experimental observation of instabilities and chaos from a two-(transverse) mode cw CO₂ laser with a predominantly homogeneously broadened lasing transition. In accordance with the theory of Shih and Milonni, chaos in this system has been found to occur through a period-doubling route (Fig. 1).

© 1987 Optical Society of America