The strong coupling of THz radiation and material excitations has potential to improve the quantum efficiency of THz devices. In this paper, we investigate a simple structure delivering THz polaritons and antipolaritons based on valence band transitions. The approach can improve the quantum efficiency of THz based devices based on TE mode in the strong coupling regime of THz radiations and intervalence bands transitions in a GaAs/AlGaAs quantum well. A Nonequilibrium Many Body Approach for the optical response beyond the Hartree–Fock approximation is used as input to the effective dielectric function formalism for the polariton/antipolariton problem. The energy dispersions relations in the THz range are obtained based on simplified analytical approximation.
R. Rungsawang, F. Perez, D. Oustinov, J. Gómez, V. Kolkovsky, G. Karczewski, T. Wojtowicz, J. Madéo, N. Jukam, S. Dhillon, and J. Tignon
http://prl.aps.org/accepted/c1072Y88G3019b3ce3be8a80c1ecd8d7ec5bd5683
We probed in the time domain, the THz electromagnetic radiation originating from spins in CdMnTe diluted magnetic semiconductors quantum wells containing high mobility electron gas. Taking advantage of the efficient Raman generation process, the spin precession was induced by low power near-infrared pulses. We provide a full theoretical first-principles description of spin-waves generation, spin precession and of emission of the THz radiation. Our results open new perspectives for improved control of the direct coupling between spins and electromagnetic field, e.g. by using semiconductor technology to insert the THz sources in cavities or pillars.
