Dynamics of time-resolved reststrahl band reflectivity in semiconductors

Summary form only given. The recent development of coherent terahertz (THz) measurement technique in the time domain has opened a way to study coherent light-matter interaction in the infrared frequency range. By using free-space electro-optic sampling technique broadband detection up to 37 THz has been demonstrated. We report on the time-resolved coherent waveform of subpicosecond infrared pulse in the reststrahl bands of polar semiconductors. We observe strong oscillations at a frequency near longitudinal optical phonons in the reflection. The damping time constants of the oscillations are shown to be comparable to those of coherent phonons. Analysing the data in different time windows gives us dynamic information on the reststrahl band optical property mediated by phonons.