Transient phase-space filling by resonantly excited exciton interactions in CuCl

We report time-resolved induced-absorption measurements near the ${\mathrm{Z}}_3$-exciton resonance in CuCl platelets which were excited at the biexciton resonance by laser pulses of 30-ps duration. We find that the excitons created through biexciton decay induce exponential tails on their absorption line. This effect can be explained in terms of exciton phase-space filling if quantum fluctuations in the local exciton density are taken into account.