Spontaneous Spatial Symmetry Breaking in a Fabry-Perot Cavity

Abstract

Spatial symmetry breaking is a common phenomenon to many systems, such as for example nonlinear chemical reactions, where dissipative structures play a dominant role. In general one is interested in situations where a system, initially in a homogeneous stationary state, develops an instability for suitable values of the control parameters and evolves into a new stationary configuration with a lower degree of symmetry [1]. Spatial symmetry breaking phenomena have also been predicted to occur in lasers with a unidirectional ring cavity configuration [2]. The typical setting involves an initial stationary state which is radially inhomogeneous because of the constraints imposed by the spherical mirrors, but which possesses cylindrical symmetry (for example, a TEM∞ mode). Under some appropriate conditions higher order transverse modes, with an angular intensity dependence, may become unstable and break the symmetry of the initial state. Most experimental lasers, however, are designed in a Fabry-Perot configuration. For this reason, we have developed a generalization of the ring laser model whose predictions can be tested more readily against a standard laboratory device