Abstract

The interaction between local modes (ω_L— vibrations associated to an impurity ion) and phonon modes (ω_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 (~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.

© 1999 Optical Society of America