Mixing collisions and quantum beats in photon echoes

Sven R. Hartmann

Mario Alex Hollberg, A. V. Trifonov, Stefan Grisard +7 more

Norman A. Kurnit, Sven R. Hartmann

Xuejun Zhu, Mark S. Hybertsen, P. B. Littlewood +1 more

Using a perturbation theory based on the density-matrix formulation, we study the nonlinear optical responses of a noninteracting three-level model system to consecutive coherent pulsed excitations, as realized in several recent experiments involving excitonic transitions in quantum wells. The terahertz emission, which is a second-order response, and the four-wave mixing signal, a third-order response, are calculated within the rotating-wave approximation, in the presence of detuning, dephasing, and inhomogeneous broadening. We study the quantum beats in the photon echo from transient four-wave mixing experiments of a three-level system. We find that the temporal profile of the photon echo signal in the four-wave mixing experiments depends very strongly on the amount of inhomogeneous broadening of the energy levels involved. Both the position and the intensity of the peaks exhibit a smooth evolution from strong quantum beats to a conventional photon echo as the inhomogeneous broadening increases. These features from our noninteracting model system are compared with a recent experiment, and found to account for a number of experimental observations.

K.‐H. Pantke, J. M. Hvam

We review quantum beats from extended electronic states in bulk semiconductors and multiple quantum well structures obtained by nonlinear spectroscopy. The nonlinear methods are degenerate four-wave mixing, photon echo and nonlinear transmission. The role of the spectral resolution of the nonlinear signal emitted from a four-wave mixing process is discussed in detail. Results obtained by linear methods like fluorescence or transmission are briefly discussed.

P. R. Berman, J. Schmidt, Richard G. Brewer