Recent Progress in Modelling Single Model Laser Instabilities

The topic of laser instabilities is one of the oldest subjects in laser research. Even before the first laser had been built, it had been demonstrated in 1958 that a simple semiclassical maser model could possess an intrinsic instability.1 A surge of interest in laser instability modelling followed the discovery that ruby lasers routinely produce their outputs in the form of infinite trains of short pulsations or "spikes".2 Since those earliest experiments, a wealth of data has been accumulated on ruby and the dozens of other laser systems that sometimes, for no apparent reason, emit infinite pulse trains. There has also been much effort expended on developing theoretical models which might account for the experimental observations, and in recent years such modelling efforts have been increasingly successful. The purpose of this presentation is to provide an overview of laser instability modelling with an emphasis on recent developments. At the outset, the various possible approaches to this subject will be briefly surveyed.