Abstract

Increasingly sophisticated models of lasers which include field diffraction effects and account for the geometry of the resonator and the lack of transverse gain uniformity have improved our ability to classify rather complex spatial and temporal behaviors; in addition, they have yielded predictions that can be tested experimentally with good qualitative accuracy.¹ In this paper we review our recent progress with the study of a Maxwell-Bloch model of a unidirectional ring laser with emphasis on the emergence of transverse patterns and intensity fluctuations. The inclusion of transverse effects produces significant quantitative and qualitative differences relative to the traditional plane wave models. In particular, these predictions include a reduced gain threshold for unstable behavior, instabilities even in the rate equation limit, the emergence of complex transverse patterns in the output intensity profile, and symmetry breaking effects. Furthermore the competition of several transverse modes, in appropriate conditions, leads to a special regime of operation in which the modes oscillate synchronously with the same frequency in what we call a cooperative frequency locked state. In these conditions stationary spatial patterns emerge with complex profiles. We attempt to characterize special complexity by means of suitable correlation functions.

© 1989 Optical Society of America