EXCITONIC BISTABILITIES, INSTABILITIES AND CHAOS IN LASER-PUMPED SEMICONDUCTORS

The Hurwitz criteria are used for a stability analysis of the steady s tate excitonic optical bistability curves in a semiconductor pumped by an external laser resonant with the exciton level. Besides the middle branch of the bistability curves which is unstable in the sense of th e linear stability theory, we have found other domains of instability in the upper and lower branches of the steady state curves. Numerical results show that a possible route to chaos in the photon-exciton syst em is period-doubling self-oscillation process. The influence of the p resence of free carriers that coexist with the excitons is also discus sed.