We investigate the reflection near the reststrahlen band of the optical phonon in bulk GaAs in the time domain, using time-resolved terahertz spectroscopy. We find that the dynamics of the reflection measured for GaAs differs strongly from the reflection dynamics that would be expected for a TO phonon with a frequency-independent dephasing time.

Opt. Lett.
Ultrafast Spectroscopy

Cho, G.C, Han, P.Y, Zhang, X.-C, & Bakker, H.J. (2000). Optical phonon dynamics of GaAs studied with time-resolved terahertz spectroscopy. Opt. Lett., 25, 1609–1611.