DESIGN AND APPLICATION OF A FEMTOSECOND OPTICAL PARAMETRIC OSCILLATORFOR TIME-RESOLVED SPECTROSCOPY OF SEMICONDUCTOR HETEROSTRUCTURES

Femtosecond pulses of a collinearly pumped Optical Parametric Oscillat or (OPO) are applied for investigations of the carrier dynamics in ter nary and quaternary semiconductor quantum wells. The design and the sp ecifications of the OPO are given in detail. We show that no measurabl e jitter exists between the pump pulses and the output pulses of the O PO. Therefore, it is possible to use the OPO and its pump laser for tw o-color experiments with a time resolution limited by the pulse length s. We present and discuss results of transient four-wave mixing experi ments on (InGa) As/InP quantum wells, and find a new kind of polarizat ion-dependent quantum beat phenomenon. In addition, non-degenerate exp eriments on quantum wells from the quaternary (InGaAl) As material sys tem, using two pulses at different wavelengths (one from the OPO and o ne from the pump laser), are discussed as a novel experimental techniq ue to study carrier trapping into quantum wells.