Polarization Dependence in the Intraband Optical Stark Effect of Quantum Wells

Abstract

Experiments and a theoretical description of the opti.ca1 intraband Stark effect in multiple quantum wells for an in-plane polarization of pump and test fields are presented. The nonlinear absorption spectra show a pronounced dependence on the angle between pump and test field polarization. For a quantitative agreement between theory and experimental results it is necessary to take the inhomogeneous distribution of the pump field into account, which is due to multiple reflections of the C 0 2 laser beam in the sample.

Intraband Optical Stark Effect in CdTe

“…In the presence of the pump field, there is a blue shift of the whole spectrum and a broadening of the absorption line. The line broadening is explained by the inhomogeneous field distribution of the pump caused by multiple reflections inside the sample [12]. The only fit parameter is then the intensity of the pump laser in front of the sample.…”

“…A detailed description of the intraband optical Stark effect and its polarization dependence in MQW systems is given in ref. [12].…”

“…The non-linear susceptibility is given by the test-driven polarization which follows from density matrix theory with light-matter interaction for the pump field. It has been shown [12] that the intraband Stark effect can be visualized by putting the vector potential into the momentum operator as p -eA(t) and treating the resulting problem in effective mass approximation. By taking into account the complex band structure of semiconductors with zinc-blende lattice the interband polarization SP(t) responding to the test field SA(t) follows from…”