Microcavity effect on the pump-probe intersubband response of multiple-quantum-well structures

We study theoretically the coherent pump-probe intersubband response of a multiple quantum well (MQW) embedded in a semiconductor microcavity. An n-type doped MQW structure with two subbands in the conduction band is considered. Self-consistent numerical calculations are performed for realistic systems employing a semiclassical approach based on the transfer matrix formalism and the so-called sheet model. They show that in the strong coupling limit the pumping of the system leads to evolution of the intersubband cavity polariton doublet into a Mollow-type spectrum. By using appropriate angles, both the pump and the probe light can be tuned into resonance with the cavity mode. In this double-resonance case, simultaneously with a dramatic enhancement of the Rabi flopping frequency, a strong selective enhancement of distinct parts of the Rabi sidebands is possible.