Terahertz Radiation Driven Nonlinear Transport Phenomena in Two-Dimensional Tellurene.

Nonlinear electron transport induced by polarized terahertz radiation is studied in two-dimensional tellurene at room temperature. A direct current, quadratic in the radiation's electric field, is observed. Contributions sensitive to radiation helicity and polarization orientation as well as polarization independent current are found.

Carbon nanotubes for polarization sensitive terahertz plasmonic interferometry.

We report on helicity sensitive photovoltaic terahertz radiation response of a carbon nanotube made in a configuration of a field-effect transistor. We find that the magnitude of the rectified voltage is different for clockwise and anticlockwise circularly polarized radiation. We demonstrate that this effect is a fingerprint of the plasma waves interference in the transistor channel.

Terahertz Photogalvanics in Twisted Bilayer Graphene Close to the Second Magic Angle.

We report on the observation of photogalvanic effects in tBLG with a twist angle of 0.6°. We show that excitation of the tBLG bulk causes a photocurrent, whose sign and magnitude are controlled by the orientation of the radiation electric field and the photon helicity.

Helicity-Sensitive Plasmonic Terahertz Interferometer.

Plasmonic interferometry is a rapidly growing area of research with a huge potential for applications in the terahertz frequency range. In this Letter, we explore a plasmonic interferometer based on graphene field effect transistor connected to specially designed antennas. As a key result, we observe helicity- and phase-sensitive conversion of circularly polarized radiation into dc photovoltage caused by the plasmon-interference mechanism: two plasma waves, excited at the source and drain part of the transistor, interfere inside the channel.

Observation of Terahertz-Induced Magnetooscillations in Graphene.

When high-frequency radiation is incident upon graphene subjected to a perpendicular magnetic field, graphene absorbs incident photons by allowing transitions between nearest Landau levels that follow strict selection rules dictated by angular momentum conservation. Here, we show a qualitative deviation from this behavior in high-quality graphene devices exposed to terahertz (THz) radiation. We demonstrate the emergence of a pronounced THz-driven photoresponse, which exhibits low-field magnetooscillations governed by the ratio of the frequency of the incoming radiation and the quasiclassical cyclotron frequency.