Dynamics of local modes during nonradiative relaxation

The direct participation of local modes in nonradiative processes taking place in impurity-doped laser crystals is investigated using time resolved resonance Raman scattering. The measured dynamics of the highest energy Cr4+ local mode in Cr:Mg2SiO4 shows that nonradiative relaxation proceeds via transfer of the nonequilibrium local mode population generated during the transition through an electronic bottleneck, to a select number of daughter phonons, and not directly, to the phonon continuum.