Abstract-“Terhune-like” transformation of the terahertz polarization ellipse “mutually induced” by three-wave joint propagation in liquid

Alexei V. Balakin, Sergey V. Garnov, Vladimir A. Makarov, Nikolay A. Kuzechkin, Petr A. Obraztsov, Peter M. Solyankin, Alexander P. Shkurinov, and Yiming Zhu

https://www.osapublishing.org/ol/fulltext.cfm?uri=ol-43-18-4406&id=396882

In this Letter, we show experimentally for the first time, to the best of our knowledge, the possibility to observe the effect of polarization mutual action of three elliptically polarized waves, with one of them at terahertz frequency, when they propagate in the isotropic nonlinear medium. When three light pulses are propagated at frequencies 𝜔$\omega$, 2𝜔$2\omega$, and 𝜔THz${\omega }_{\mathrm{THz}}$ through liquid nitrogen, we observed the rotation of the ellipse main axis and the ellipticity change. We have shown that this effect is very well described theoretically in the framework of a physical approach analogous to the self-rotation of the polarization ellipse first described in 1964 by Maker et al., but expanded for the case of multi-frequency interaction.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Ultrafast zero-bias photocurrent and terahertz emission in hybrid perovskites

Petr A. Obraztsov, Dmitry Lyashenko, Pavel A. Chizhov, Kuniaki Konishi, Natsuki Nemoto, Makoto Kuwata-Gonokami, Eric Welch, Alexander N. Obraztsov,  Alex Zakhidov,

https://www.nature.com/articles/s42005-018-0013-8

Methylammonium lead iodide is a benchmark hybrid organic perovskite material used for low-cost printed solar cells with a power conversion efficiency of over 20%. Nevertheless, the nature of light–matter interaction in hybrid perovskites and the exact physical mechanism underlying device operation are currently debated. Here, we report room temperature, ultrafast photocurrent generation, and free-space terahertz emission from unbiased hybrid perovskites induced by femtosecond light pulses. The polarization dependence of the observed photoresponse is consistent with the bulk photovoltaic effect caused by a combination of injection and shift currents. Observation of this type of photocurrents sheds light on the low recombination and long carrier diffusion lengths arising from the indirect bandgap in CH3NH3PbI3. Naturally ballistic shift and injection photocurrents may enable third-generation perovskite solar cells with efficiency exceeding the Shockley–Queisser limit. The demonstrated control over photocurrents with light polarization also opens new venues toward perovskite spintronics and tunable THz devices.

Abstract-Ultrafast polarization control of zero-bias photocurrent and terahertz emission in hybrid organic perovskites

Petr A. Obraztsov, Dmitry Lyashenko, Pavel A. Chizhov, Kuniaki Konishi, Natsuki Nemoto, Makoto Kuwata-Gonokami, Eric Welch, Alexander N. Obraztsov, Alex Zakhidov

(Submitted on 26 Oct 2017)

https://arxiv.org/abs/1710.09728

Methylammonium lead iodide (MAPI) is a benchmark hybrid organic perovskite material, which is used for the low-cost, printed solar cells with over 20 percent power conversion efficiency. Yet, the nature of light-matter interaction in MAPI as well as the exact physical mechanism behind device operation is currently debated. Here we report room temperature, ultrafast photocurrent and freespace terahertz (THz) emission generation from unbiased MAPI induced by 150 fs light pulses. Polarization dependence of the observed photoresponse is consistent with the Bulk Photovoltaic Effect (BPVE) caused by a combination of injection and shift currents. We believe that this observation of can shed light on low recombination, and long carrier diffusion lengths due to indirect bandgap. Moreover, ballistic by nature shift and injection BPVE photocurrents may enable third generation perovskite solar cells with efficiency that exceed the Shockley_Queisser limit. Our observations also open new venues for perovskite spintronics and tunable THz sources.

Abstract-Photon-drag-induced terahertz emission from graphene

Petr A. Obraztsov1,2,*, Natsuki Kanda3,4, Kuniaki Konishi5, Makoto Kuwata-Gonokami4,5,6, Sergey V. Garnov1, Alexander N. Obraztsov2,7, and Yuri P. Svirko2

• 1A. M. Prokhorov General Physics Institute, Moscow, Russia
• 2Department of Physics and Mathematics, University of Eastern Finland, Joensuu, Finland
• 3Laser Technology Laboratory, RIKEN, Saitama, Japan
• 4Photon Science Center, The University of Tokyo, Tokyo, Japan
• 5Institute for Photon Science and Technology, The University of Tokyo, Tokyo, Japan
• 6Department of Physics, The University of Tokyo, Tokyo, Japan
• 7Department of Physics, M. V. Lomonosov Moscow State University, Moscow, Russia

• *p.obraztsov@gmail.com
• https://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.241416

We report the investigation of a strong interband photon drag effect in multilayer graphene leading to efficient emission of terahertz radiation. The obtained terahertz photoresponse of graphene layers exhibits peculiarities fundamentally predicted for free carrier transport in two-dimensional electronic systems. Owing to significant light absorption in gapless graphene, where each absorbed photon produces an electron-hole pair with the highest possible kinetic energy, the photon drag mechanism provides a possibility to achieve efficient conversion of light into broadband terahertz radiation as well as new ways towards vectorial control of the generated terahertz radiation in graphene-based materials.

DOI: http://dx.doi.org/10.1103/PhysRevB.90.241416

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• Published 29 December 2014
• Received 9 October 2014

©2014 American Physical Society