Imprisonment of Resonant Phonons Observed with a New Technique for the Detection of1012-Hz Phonons

Abstract

A new technique for the monochromatic detection of ${10}^{12}$-Hz phonons is applied to the study of 20-${\mathrm{cm}}^{-1\mathrm{}}$ phonons in ruby. The resolution of the phonon detector in space and time allows the observation of the local imprisonment of 29-${\mathrm{cm}}^{-1\mathrm{}}$ phonons in a ruby crystal that contains variable concentrations of ${\mathrm{Cr}}^{3+}$ ions in the excited $\overline{E}\left({}_{}{}^2{}_{}{}^{}E\right)$ state. The application for the determination of the lifetime of ${10}^{12}$-Hz phonons is discussed.