"Ultrafast Optical and Terahertz Effects in Semiconductor Nanostructures."

"Resonant optical excitation of semiconductors creates an interband polarization that can decay via re-radiation or interaction-induced conversion into quasi-particle excitations such as electron-hole plasma and/or excitons. With the help of time-delayed pulses with central frequencies in the terahertz (THz) range, one can induce transitions between the eigenstates of the temporally developing many-body system. Besides the characterization of the momentary excitation state, this combined optical and THz time-domain scheme allows for deliberate quantum-state manipulation, excitation shelving into optically dark states, transient exciton ionization, as well as high-harmonic generation."