Abstract

The spatio-temporal dynamics of a Laser with intracavity Saturable Absorber (LSA) is analyzed in order to determine the role played by the absorber in the formation of the transverse patterns. The analytical study has been made on 3-2 level model for a LSA, including diffraction effects, as derived by Barsella et al. [1]. We perform a linear stability analysis near the non lasing solution in order to find the structure which will emerge at laser threshold. We demonstrate that the role of the absorber parameters is to select or to inhibit transverse structures depending on the sign of a new physical parameter corresponding to an “effective detuning” characterizing the whole LSA system. A weakly non-linear stability analysis and a derivation of the amplitude equations for the laser intensity are performed. Numerical simulations based upon these equations lead to a regular periodic pattern (see Figure). We notice that this 4-components pattern is similar to those reported in hydrodynamics by Silber et al. and recently by Komarova et al. [2].

© 1998 IEEE