Abstract

Optical excitation of activated crystals is usually accompanied by the creation of "relaxation" phonons in the lattice (the "Stokes losses"). At low temperatures when the equilibrium phonon occupancies are small the nonequilibrium phonons thus formed may affect markedly the processes involving excited impurity ions and their luminescence characteristics. Investigation of luminescence effects associated with the nonequilibrium phonons provides valuable information on the dynamic processes in the excited state, on the various mechanisms of phonon interaction with impurity ions, as well as on the characteristics of the phonons proper, primarily of the terahertz range acoustic phonons.

© 1984 Optical Society of America