Ultrafast coherently controlled currents in GaAs: physics and applications

Abstract

This thesis gives new insights into the physics and practical applications of coherently controlled current injection (QUIC) in the prototypical direct band gap semiconductor GaAs. QUIC is a nonlinear optical process that allows to inject electrical currents into solids by all-optical means using two-color laser pulse pairs. The direction of the induced current can be controlled by the relative phase of the pulses. Theoretical calculations predict significant deviations from the original perturbative description of QUIC at elevated excitation intensities. The first part of the thesis presents a collaborative experimental and theoretical study of this regime. In the second part it is demonstrated that QUIC can be utilized to characterize the temporal profile of ultrashort laser pulses. The last part of this thesis discusses the experimental implementation of a proposed QUIC-based current detection scheme.