Subpicosecond spectroscopy of the optical nonlinearities of CuCl quantum dots

We have observed of ultrafast time-resolved nonlinear optical absorption spectra of confined excitons in CuCl quantum dots embedded in a NaCl matrix. The main part of the nonlinear change consisted of blueshifts of the Z3 and Z12 exciton bands, and their decay had two time constants that coincide with the luminescence lifetimes of excitons and of excitonic molecules. A microscopic mechanism for the optical nonlinearities of confined excitons is discussed.