Temperature effects in nonequilibrium phonon decay.

Abstract

We have investigated the spectral and temporal dynamics associated with the interaction between monochromatic and thermal phonon distributions in YAG:${\mathrm{Pr}}^{3+}$. Using defect-induced one-phonon absorption to generate a monochromatic phonon distribution at 43.3 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$, we measure a ${\mathit{T}}^{\mathrm{\ensuremath{-}}3}$ dependence of the monochromatic phonon lifetime in the temperature range 9 to 25 K. We observe the evolution of additional broadband phonon distributions which do not occur at low temperatures.