Creation of highly anisotropic wave packets in quantum wells: Dynamical Franz-Keldysh effect in the optical and terahertz regimes

We study the dynamical Franz-Keldysh effect by subjecting a semiconductor quantum well to both a strong THz-frequency driving field and a weak broadband optical pulse. Coulombic effects and the THz field are included nonperturbatively. Our results show THz sidebands in the optical absorption spectrum and harmonically generated subpicosecond bursts of radiation in the THz regime. The propagating wave packets are simultaneously analyzed and applications are discussed.