Christoph Drexler

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We observe photocurrents induced in single-layer graphene samples by illumination of the graphene edges with circularly polarized terahertz radiation at normal incidence. The photocurrent flows along the sample edges and forms a vortex. Its winding direction reverses by switching the light helicity from left to right handed. We demonstrate that the(More)
We report on the observation of magnetic quantum ratchet (MQR) effect induced by electric field of terahertz radiation in single-layer graphene samples subjected to an inplane magnetic field. We show that the dc electric current stems from the orbital asymmetry of the Dirac fermions induced by an in-plane magnetic field, while the periodic driving comes(More)
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Graphene has unique optical and electronic properties that make it attractive as an active material for broadband ultrafast detection. We present here a graphene-based detector that shows 40-picosecond electrical rise time over a spectral range that spans nearly three orders of magnitude, from the visible to the far-infrared. The detector employs a large(More)
P. Olbrich,1 C. Drexler,1 L. E. Golub,2 S. N. Danilov,1 V. A. Shalygin,3 R. Yakimova,4 S. Lara-Avila,5 S. Kubatkin,5 B. Redlich,6 R. Huber,1 and S. D. Ganichev1 1Terahertz Center, University of Regensburg, 93040 Regensburg, Germany 2Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia 3St. Petersburg State(More)
P. Olbrich,1 C. Zoth,1 P. Lutz,1 C. Drexler,1 V. V. Bel’kov,2 Ya. V. Terent’ev,2 S. A. Tarasenko,2 A. N. Semenov,2 S. V. Ivanov,2 D. R. Yakovlev,2,3 T. Wojtowicz,4 U. Wurstbauer,5 D. Schuh,1 and S. D. Ganichev1 1Terahertz Center, University of Regensburg, 93040 Regensburg, Germany 2Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St.(More)
We report on microwave (mw) radiation induced electric currents in semimagnetic CdMnTe and nonmagnetic InAs: Si quantum wells subjected to an external in-plane magnetic field. The current generation is attributed to the spin-dependent energy relaxation of electrons heated by mw radiation.
We report on the observation of the terahertz radiation induced edge photogalvanic effect. The directed net electric current is generated in single layer graphene by the irradiation of the samples' edges with linearly or circularly polarized terahertz laser radiation at normal incidence. We show that the directed net electric current stems from the sample(More)
Transmission spectra of wet human teeth and dentin slices, together with blood of different flow rates were investigated over a wide spectral range, from visible to terahertz (THz) light. The results make it possible to find the optimum light frequency for an all-optical determination of pulpal blood flow and, consequently, for clinically diagnosis of tooth(More)
We report on the experimental and theoretical study of the Reststrahlen Band assisted photocurrents in epitaxial grown graphene on SiC. We show that excitation of graphene with infrared radiation results in a dc current. We demonstrate that photocurrent in response to linearly polarized radiation exhibit a resonance enhancement in the frequency range of the(More)