Regensburg 2016 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 36: Poster Ib

HL 36.18: Poster

Tuesday, March 8, 2016, 15:00–19:00, Poster A

Terahertz spectroscopy and ultrafast electron dynamics of a broad single GaAs/AlGaAs quantum well — •Johannes Schmidt^{1, 2}, Stephan Winnerl¹, Martin Teich¹, Aaron M. Andrews³, Gottfired Strasser³, Harald Schneider¹, and Manfred Helm^{1, 2} — ¹Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany — ²Technische Universität Dresden, 01062 Dresden, Germany — ³Technische Universität Wien, A-1040 Vienna, Austria

Ultrafast electron dynamics in quantum well (QW) structures is investigated by applying a strong terahertz (THz) field with a photon energy resonant to an intersubband transition. In particular, if the THz field is in resonance with the transition between the second and third subband, so-called Autler-Townes (or AC Stark) splitting could be observed when probing the 1-2 transition. This effect has been observed previously at mid-infrared wavelengths in an n-type multiple QW [1]. Our efforts aim at investigating the AC-Stark effect in the THz regime using a broad, 36 nm wide single QW where the carrier density can be tuned electrically. We will present our first results indicating absorption by an intersubband transition in the QW, where the electron population can be controlled by an electrical modulation technique. Furthermore, ultrafast electron dynamics in the ps-regime is investigated by narrowband single-color pump-probe measurements performed using a THz free-electron laser.

[1] J. F. Dynes, M. D. Frogley, M. Beck, J. Faist, and C. C. Phillips, Phys. Rev. Lett. 94, 157403 (2005)