Chirped-pulse control of carriers in semiconductors: the role of many-body effects

摘要

The possibility of realizing adiabatic rapid passage (ARP) with an intense chirped-pulse excitation (a concept well known in molecular systems) in direct-gap semiconductors is studied. Based on the semiconductor Bloch equations, the analysis shows that, in spite of complications due to band structure, signatures of ARP accompanied by an intrapulse pump-dump process (IPDP) should be observable in the dependence of the carriers' density on the chirp rate in the frequency domain. The bandgap shrinkage, which is the main many-body effect, gives the dominant contribution to the asymmetry of this dependence on the chirp sign. We show that the bandgap shrinkage enlarges the carriers' density and makes a major impact on the interplay of ARP with IPDP, enhancing ARP (suppressing IPDP) for positive chirped-pulse excitation and suppressing ARP (enhancing IPDP) for negative chirped-pulse excitation. (c) 2005 Optical Society of America