Relaxation Process of Excitonic Molecules in CuCl under the Two-Photon Resonant Excitation. II. Transverse Relaxation

Abstract

Under the off-resonant excitation at the slightly higher energy side of the giant two-photon absorption band (GTA) for the direct generation of excitonic molecules (EM) in CuCl, new narrow emission bands designated as X_T and X_L have been found in the energy region of the M_T and M_L broad bands, respectively. Their photon energies increase with the decrease of the pump photon energy from the higher-energy side of the resonance and finally, at the on-resonant excitation, their bands merge into M_T⁰ and M_L⁰ bands, respectively, previously reported by Mita et al. Based on the detailed studies on these bands, it is found that there exists a certain kind of transverse relaxation process which acts on the EM just after their generation by the GTA and brings about the X emission as a hot luminescence.