STRATIFICATION AND SWITCHING FRONTS IN A COHERENT-STATE OF EXCITONS SUSTAINED BY OPTICAL-PUMPING

Instabilities of a coherent state of Wannier-Mott excitons sustained by a resonant pumping wave in cavity and cavityless cases are analysed. In particular, instability with respect to spatially periodic stratification can exist. The period of such stratification is L similar to L(ex) = [(h) over bar/m gamma](1/2), where m is the effective exciton mass, and gamma is the reciprocal exciton lifetime. The results of numerical modelling of corresponding non-linear structures are presented. For 'exciton-pumping' bistability, non-monotonic switching fronts are demonstrated numerically.