Spectroscopy and Four-Wave Mixing in Li4Ge5O12:Mn(4+) Crystals

摘要

The absorption and fluorescence spectra of Mn4+ in Li4Ge5O12 crystals are reported and the temperature dependences of the fluorescence intensity and lifetime are described. The spectral features are consistent with the presence of two types of sites for the Mn4+ ions, and radiationless decay and vibronic transitions are shown to be responsible for the variation of the spectral properties with temperature. Four-wave mixing measurements were performed with the laser excitation wavelength in resonance with an absorption transition of the Mn4+ ions. The characteristics of the four-wave mixing signal are consistent with scattering from a laser-induced population grating and the temperature dependence of the signal is correlated with the temperature dependence of the fluorescence lifetime.