Optical absorption by a semiconductor in the presence of intense radiation fields

Motivated by a recent experiment, the author presents a theoretical study on optical absorption in a semiconductor subjected to pump and probe radiation fields. The electron and hole interactions with midinfrared pump and probe fields are considered and the absorption coefficient is calculated on the basis of a Boltzmann equation approach. It is found that the results obtained theoretically are in line with those observed experimentally and can be used to understand important experimental findings such as the optical absorption in the forbidden zone and the dependence of the absorption of the probe field on intensity and frequency of the pump field. (c) 2006 American Institute of Physics.