Ultrafast dynamics in highly excited semiconductors, at Seminar in the Institute of Electronic Structure and Laser (IESL), Foundation for Reaserch and Technology - Hellas (FORTH) (Heraklion, Crete, Greece), Friday, January 7, 2005:
    A pump-probe technique measuring the dielectric function is presented and applied in a series of experiments. An ultrafast semiconductor-to-metal phase transition is observed in highly excited GaAs. High amplitude coherent phonon dynamics in Te are resolved suggesting a THz-driven semiconductor-semimetal transition. Coherent control including both enhancement and cancellation of the lattice vibrations in Te is demonstrated revealing a departure from the low-excitation behavior of similar materials.