Abstract
Picosecond free electron lasers (FEL) have been used to perform time-resolved pump-probe spectroscopy in the mid infrared. We present a Boltzmann equation formalism for modeling FEL pump-probe experiments on -type GaAs quantum wells. We model experiments in which an FEL pump is used to promote electrons from the first subband into the second subband. In our model the photoexcited electrons are allowed to relax back to the first subband via LO optical phonon scattering, LA acoustic phonon scattering, electron-electron Coulomb scattering, and scattering by ionized impurities in the quantum well. We compute the time-dependent distribution functions for electron in each subband and from the distribution functions compute the upper state lifetime, an important parameter for device applications.
- Received 23 July 1997
DOI:https://doi.org/10.1103/PhysRevB.57.9148
©1998 American Physical Society