TEMPERATURE, TEMPORAL AND CONCENTRATION-DEPENDENCE OF LASER-NARROWED D-5(0)-]F-7(0) FLUORESCENCE LINESHAPE OF EU3+ IN GLASSES

Time-resolved laser-induced fluorescence line-narrowing -techniques employing gated vidicon detection have been used to study the homogeneous resonance fluorescence linewidth of the 5D0 → 7F0 transition of Eu3+ at low concentration in Inorganic glasses. The linewidth is shown to be determined by the rate of phase-interrupting, two-phonon Raman scattering processes. The efficiency of these processes is found to be sensitive to the strength of the crystal field of the particular site in which a Eu3+ ion sits. At higher concentrations, the laser-narrowed fluorescence lineshape becomes time-dependent, due to site-to-site phonon-assisted energy transfer processes. Its Intensity is found to decrease (retaining the same value for its half-width) while a growth of the inhomogeneous line profile is observed as time elapses after the initial laser excitation. From this behavior, the transfer rate is determined and studied as a function of concentration, temperature, and wavelength of excitation. We conclude that the electronic coupling mechanism is dipolar in nature and the phonon assistance occurs via a two-phonon Raman process with one phonon scattered at each of the coupled sites. © 1978.