Symmetry of 2P excitonic wave function in strained ZnSe

The symmetry of the 2P excitonic wave functions in strained ZnSe thin films is directly investigated for the first time in the time domain by using a coherent control technique with a phase-locked pulse pair. When the incident photon energy is two-photon resonant with the 2P exciton levels, the interferogram of the hyper-Rayleigh scattering is strongly dependent on the polarization angle between the phase-locked pulse pair. The resultant data show that the heavy hole 2P exciton belongs to an s-like base function and the light hole 2P exciton to a d-like base function under the two-photon excitation regime.