Intraband Dynamics and Terahertz Emission in Biased GaAs/In0.53Ga0.47As Semiconductor Superlattices

Abstract

Using an excitonic basis, we investigate the intraband polarization, optical absorption spectra, and terahertz emission of semiconductor superlattice with the density matrix theory. The excitonic Bloch oscillation is driven by the dc and ac electric fields. The slow variation in the intraband polarization depends on the ac electric field frequency. The intraband polarization increases when the ac electric field frequency is below the Bloch frequency. When the ac electric field frequency is above the Bloch frequency, the intraband polarization downwards and its intensity decreases. The satellite structures in the optical absorption spectra are presented. Due to excitonic dynamic localization, the emission lines of terahertz shift in different ac electric field and dc electric field.