Optical Phonon Lifetime Measured Directly with Picosecond Pulses

The lifetime of the 1086-cm^-1 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.