PUMP-PROBE STUDIES OF CARRIER CAPTURE PROCESSES IN SEMICONDUCTOR MULTIPLE-QUANTUM-WELL WAVE-GUIDES

Carrier capture processes in multiple-quantum-well (MQW) waveguides ar e monitored using the time-resolved pump-probe technique, With appropr iate selections of wavelength and pulse recompression, subpicosecond p ulses at various wavelengths can be obtained for both nondegenerate an d degenerate pump-probe experiments with various polarization combinat ions, Two samples of different quantum-well structures are compared, I t is found that the carrier capture times (defined as the time period to reach probe transmission maximum after the pump) are in the range f rom 15 to 50 ps in the samples used, In the degenerate pump-probe meas urements, a two-component decay is observed for one of the samples in the case of TM pump and TE probe.