ULTRAFAST COHERENT CONTROL AND DESTRUCTION OF EXCITONS IN QUANTUM-WELLS

We demonstrate the coherent destruction of photogenerated excitons in semiconductor quantum wells within a few hundred femtoseconds of their excitation. Coherent control of carrier dynamics is achieved with pha se-locked pairs of 100 fs infrared pulses. The technique induces an op tical response which is faster than the inverse of the exciton linewid th superseding Fourier limits for a single pulse. Energy selectivity e nables the coherent transfer of angular momentum between hole states. Such phase-tailored pulse trains can be utilized to investigate the ge neration process and intermediate virtual states in quantum structures .