Abstract-Magnetoresistance oscillations induced by high-intensity terahertz radiation

T. Herrmann, Z. D. Kvon, I. A. Dmitriev, D. A. Kozlov, B. Jentzsch, M. Schneider, L. Schell, V. V. Bel’kov, A. Bayer, D. Schuh, D. Bougeard, T. Kuczmik, M. Oltscher, D. Weiss, and S. D. Ganichev

https://journals.aps.org/prb/accepted/7a079Oe8S5a1573025948ef2a7974268293e8629a

We report on observation of pronounced terahertz radiation-induced magneto-resistivity oscillations in AlGaAs/GaAs two-dimensional electron systems, the THz analog of the microwave induced resistivity oscillations (MIRO). Applying high power radiation of a pulsed molecular laser we demonstrate that MIRO, so far observed at low power only, are not destroyed even at very high intensities. Experiments with radiation intensity ranging over five orders of magnitude from 0.1 W/cm2 to 104 W/cm2 reveal high-power saturation of the MIRO amplitude, which is well described by an empirical fit function I/(1+I/I_s)^\beta with \beta~\sim 1. The saturation intensity I_s is of the order of tens of W/cm2and increases by six times by increasing the radiation frequency from 0.6 to 1.1~THz. The results are discussed in terms of microscopic mechanisms of MIRO and compared to nonlinear effects observed earlier at significantly lower excitation frequencies.

Abstract-Magneto-resistance oscillations induced by high-intensity terahertz radiation

T. Herrmann, Z. D. Kvon, I. A. Dmitriev, D. A. Kozlov, B. Jentzsch, M. Schneider, L. Schell, V. V. Bel'kov, A. Bayer, D. Schuh, D. Bougeard, T. Kuczmik, M. Oltscher, D. Weiss, S. D. Ganichev

(Submitted on 22 Jun 2017)

https://arxiv.org/abs/1706.07239

We report on observation of pronounced terahertz radiation-induced magneto-resistivity oscillations in AlGaAs/GaAs two-dimensional electron systems, the THz analog of the microwave induced resistivity oscillations (MIRO). Applying high power radiation of a pulsed molecular laser we demonstrate that MIRO, so far observed at low power only, are not destroyed even at very high intensities. Experiments with radiation intensity ranging over five orders of magnitude from 0.1 W/cm2 to 104 W/cm2 reveal high-power saturation of the MIRO amplitude, which is well described by an empirical fit function I/(1+I/Is)β with β∼1. The saturation intensity Is is of the order of tens of W/cm2 and increases by six times by increasing the radiation frequency from 0.6 to 1.1 THz. The results are discussed in terms of microscopic mechanisms of MIRO and compared to nonlinear effects observed earlier at significantly lower excitation frequencies.

Abstract-Helicity sensitive terahertz radiation detection by dual-grating-gate high electron mobility transistors

P. Faltermeier¹, P. Olbrich¹, W. Probst¹, L. Schell¹, T. Watanabe², S. A. Boubanga-Tombet², T. Otsuji² and S. D. Ganichev¹
http://scitation.aip.org/content/aip/journal/jap/118/8/10.1063/1.4928969
1 Terahertz Center, University of Regensburg, 93040 Regensburg, Germany
2 Research Institute of Electrical Communication, Tohoku University, 980-8577 Sendai, Japan
J. Appl. Phys. 118, 084301 (2015); http://dx.doi.org/10.1063/1.4928969

We report on the observation of a radiation helicity sensitive photocurrent excited by terahertz (THz) radiation in dual-grating-gate (DGG) InAlAs/InGaAs/InAlAs/InP high electron mobility transistors (HEMT). For a circular polarization, the current measured between source and drain contacts changes its sign with the inversion of the radiation helicity. For elliptically polarizedradiation, the total current is described by superposition of the Stokes parameters with different weights. Moreover, by variation of gate voltages applied to individual gratings, the photocurrentcan be defined either by the Stokes parameter defining the radiation helicity or those for linearpolarization. We show that artificial non-centrosymmetric microperiodic structures with a two-dimensional electron system excited by THz radiation exhibit a dc photocurrent caused by the combined action of a spatially periodic in-plane potential and spatially modulated light. The results provide a proof of principle for the application of DGG HEMT for all-electric detection of the radiation's polarization state.