Terahertz nonlinear optics of exciton states


Terahertz nonlinear optics of exciton states

Helm, M.

Excitons in semiconductor exhibit a hydrogenic energy spectrum, scaled down into the THz range. By pumping the 1s-2p intra-excitonic transition in GaAs/AlGaAs quantum wells with the Dresden free-electron laser, we induce an AC Stark effect, namely the famous Autler-Townes splitting reflecting exciton states dressed by THz photons [1]. The spectrum is probed via band-gap absorption. Under similar conditions, we also observe resonantly enhanced THz sideband generation by mixing the THz and band gap radiation [2].
[1] M. Wagner et al., Phys. Rev. Lett. 105, 167401 (2010)
[2] M. Wagner et al., Appl. Phys. Lett. 94, 241105 (2009)

Keywords: terahertz; exciton; free-electron laser

Related publications

  • Invited lecture (Conferences)
    Workshop of the GDRI-CNRS: Semiconductors Sources and Detectors of THz Radiation, 29.03.-01.04.2011, Tignes, France

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