Features of strong coherent excitation of microcavities containing quantum wells

Abstract

Summary form only given. We present time resolved pump and probe measurements, in the strong excitation regime, of a semiconductor microcavity (MC) containing quantum wells (QWs). The fundamental QW exciton (X) and the cavity mode were resonant or slightly detuned, while the energy of the laser photons was chosen to be dose to the energy of the photon like polariton. The investigated MCs are high finesse heterostructures made of GaAs/GaAlAs layers, featuring cavity-mode line widths of at most 0.7 meV. The GaAs spacer layer contains one or several InGaAs QWs positioned at the anti-nodes of the electric field. At low excitation densities, the X-cavity system is in the strong coupling regime. The X level is more or less inhomogeneously broadened, its width varies between five and a few tenths of meV. The measurements were done at near normal incidence, using 100 fs long laser pulses. Pump-probe delays /spl Delta/t close to zero were chosen, for which the X-photon system inside the cavity is coherent. The transmitted and reflected intensities of the probe vs wavelength, pump intensity and pump-probe delay have been measured.