The lifetime of the 1086-${\mathrm{cm}}^{-1\mathrm{}}$ optical phonon in calcite is measured directly to be 8.5 ± 2 psec at 297°K and 19.1 ± 4 psec at 100°K by using a picosecond laser beam to create the phonons by stimulated Raman scattering, and then observing Raman scattering off the phonons at various delay times with a weaker picosecond beam at another frequency.

• Received 20 January 1971

DOI:https://doi.org/10.1103/PhysRevLett.26.1247