Circularly polarized dynamic Franz-Keldysh effect

Abstract

We consider the optical properties associated with the photoexcitation and radiative recombination of free electron-hole pairs and excitons in an intrinsic quantum well in a strong THz-frequency electric field, namely the cw optical transmission and reflection through the quantum well for linearly and circularly in-plane polarized THz fields. We first neglect the electron-hole Coulomb interaction, which is associated with the Sommerfeld factor and the formation of excitons. For the linear case, the optical spectra exhibit a series of THz sidebands whose spacing is given by twice the THz frequency; for the circular case, no sidebands occur. Next, the electron-hole Coulomb interaction is included in the limit of strong driving fields; the THz sidebands for circularly polarized fields are strongly suppressed. These features are explained by the classical and quantum dynamics of driven free particles, and are reproduced by detailed numerical solution of the semiconductor Bloch equations.