Two-photon excitation spectra of confined excitons in CuCl nanocrystals

We investigated two-photon excitation spectra of confined excitons of CuCl nanocrystals embedded in a NaCl matrix. The spectra exhibit a sharp increas e that is attributed to transitions into higher Coulombic states (n P) of t he confined excitons, and its position shifts to a higher energy side with decreasing crystal size. We also discuss the difference in peak positions b etween one- and two-photon absorption spectra in the presence of a broad in homogeneous width due to the size distribution.