Intrinsic Luminescence in KI and RbI under Two-Photon Excitation

Abstract

It has been confirmed that KI and RbI crystals under the two-photon excitation by a dye laser exhibit three emission bands at 3.05 eV, 3.31 eV, 4.10 eV and 2.27 eV, 3.12 eV, 3.96 eV, respectively, which are the same as those under the conventional one-photon excitation at low temperature. The intensity of the 3.05 eV and 3.31 eV emissions in KI decay with respective two decay times. The fast and slow components of these emissions exhibit almost identical emission spectra with the half width of 0.33±0.03 eV. The 2.27 eV and 3.12 eV emissions in RbI decay also by the fast and slow decay times. Temperature dependence of the decay time and intensity of these emissions has been studied, and possible electronic states responsible for these emissions are discussed.