Role of intra-, inter-molecular and resonance decay pathways in nonradiative processes taking place in impurity-doped laser crystals

Summary form only given. The interaction between local modes (/spl omega//sub L/-vibrations associated to an impurity ion) and phonon modes (/spl omega//sub P/-vibrations associated to the lattice host) plays a crucial role in determining the strength of nonradiative processes taking place in impurity-doped laser crystals. Following photoexcitation of an impurity ion, nonradiative processes proceed through the following succession of steps: (1) a transition through an electronic bottleneck (towards a lower lying electronic state) generates a large local mode population; (2) the energy stored for a brief time (/spl sim/ps) in local modes is transferred to select phonon modes via harmonic and/or anharmonic interactions; and; (3) the "active" phonon modes interact with the phonon bath and bring the system back to thermal equilibrium. Our work has focused on the interaction between the local and phonon subsystems.