Nonlinear optical response of hole-trion systems in quantum dots in tilted magnetic fields

We discuss, from a theoretical point of view, the four wave mixing spectroscopy on an ensemble of p-doped quantum dots in a magnetic field slightly tilted from the in-plane configuration. We describe the system evolution in the density matrix formalism. In the limit of coherent ultrafast optical driving, we obtain analytical formulas for the single system dynamics and for the response of an inhomogeneously broadened ensemble. The results are compared to the previously studied time-resolved Kerr rotation spectroscopy on the same system. We show that the Kerr rotation and four wave mixing spectra yield complementary information on the spin dynamics (precession and damping). (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim