Ultrafast transverse and longitudinal response of laser-excited quantum wires.

Abstract

We couple 1D pulse propagation simulations with laser-solid dynamics in a GaAs quantum wire, solving for the electron and hole populations and the interband and intraband coherences between states. We thus model not only the dynamical dipole contributions to the optical polarization (interband bound-charge response) but also the photo-generation and back-action effects of the net free-charge density (intraband free-charge response). These results show that solving for the dynamic electron and hole intraband coherences leads to plasma oscillations at THz frequencies, even in a 1D solid where plasma screening is small. We then calculate the transverse and longitudinal response of the quantum wire and characterize the dispersion relation for the e-h plasma. This approach allows one to predict the optoelectronic response of 1D semiconductor devices during and after exposure to resonant ultrashort pulses.