Memory effects and dynamics of optical bistability in CuCl

We study the time variation of the nonlinear absorption due to the creation of biexcitons by a high-intensity nanosecond pulsed laser in CuCl. We show that this variation is different at the beginning and at the end of the laser pulse. This memory effect depends on the photon energy and on the intensity of the laser beam. An explanation based on the time dependence of the population is suggested. We also make a time analysis of a bistable device composed of a sample of CuCl placed in a Fabry-Pérot cavity. The switching times measured are of some hundredths of picoseconds. We stress the importance of the absorption present in the cavity and show that it may destroy the dispersive bistability. Finally, we give some trends of the spatial variation of hysteresis in the transverse section of the laser beam.