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Terahertz (THz) technology is a growing and multi-disciplinary research field, particularly for sensing and telecommunications. A number of THz waveguides have emerged over the past years, which are set to complement the capabilities of…

We present an electrically switchable graphene terahertz (THz) modulator with a tunable-by-design optical bandwidth and we exploit it to compensate the cavity dispersion of a quantum cascade laser (QCL). Electrostatic gating is achieved by…

Flexible energy harvesting devices fabricated in scalable thin-film processes are important components in the field of wearable electronics and the Internet of Things. We present a flexible rectenna based on a one-dimensional junction…

We report on the engineering of broadband quantum cascade lasers (QCLs) emitting at Terahertz (THz) frequencies, which exploit a heterogeneous active region scheme and have a current density dynamic range (Jdr) of 3.2, significantly larger…

Exploration of optical non-linear response of graphene predominantly relies on ultra-short time domain measurements. Here we propose an alternate technique that uses frequency modulated continuous wavefront optical fields, thereby probing…

Mesoscale and Nanoscale Physics · Physics 2019-03-18 Ashutosh Singh , Saikat Ghosh , Amit Agarwal

To efficiently integrate cutting-edge terahertz technology into compact devices, the highly confined terahertz plasmons are attracting intensive attentions. Compared to plasmons at visible frequencies in metals, terahertz plasmons,…

Optics · Physics 2021-05-18 Jianfeng Wang , Xuelei Sui , Wenhui Duan , Feng Liu , Bing Huang

We report a plasma-based strong THz source generated by using intense femtosecond laser pulses to irradiate solid targets at relativistic intensity >10^18W/cm2. Energies up to 50 microJ/sr per THz pulse is observed in the specular direction…

We theoretically study the generation of terahertz (THz) radiation by two-color filamentation of ultrashort laser pulses with different wavelengths. We consider wavelengths in the range from 0.6 to 10.6 $\mu$m, thus covering the whole range…

Optics · Physics 2018-08-20 Vladimir Yu. Fedorov , Stelios Tzortzakis

In the presence of strong magnetic fields the electronic bandstructure of graphene drastically changes. The Dirac cone collapses into discrete non-equidistant Landau levels, which can be externally tuned by changing the magnetic field. In…

Mesoscale and Nanoscale Physics · Physics 2017-07-26 Samuel Brem , Florian Wendler , Ermin Malic

We demonstrate that phase-difference between terahertz signals on the source and drain of a field effect transistor (a TeraFET) induces a plasmon-assisted dc current, which is dramatically enhanced in vicinity of plasmonic resonances. We…

Mesoscale and Nanoscale Physics · Physics 2019-02-20 I. V. Gorbenko , V. Yu. Kachorovskii , Michael Shur

Graphene is a promising candidate for the development of detectors of Terahertz (THz) radiation. A well-known detection scheme due to Dyakonov and Shur exploits the confinement of plasma waves in a field-effect transistor (FET), whereby a…

Mesoscale and Nanoscale Physics · Physics 2013-12-06 Andrea Tomadin , Alessandro Tredicucci , Vittorio Pellegrini , Miriam S. Vitiello , Marco Polini

We propose a new energy conversion approach from a dc electric field to a terahertz wave based on hybrid semiconductors by combining two-dimensional (2D) crystalline layers and a thick conducting material with possible applications as a…

Mesoscale and Nanoscale Physics · Physics 2015-09-02 Godfrey Gumbs , Andrii Iurov , Danhong Huang , Wei Pan

Terahertz (THz) radiation is a powerful tool with widespread applications ranging from imaging, sensing, and broadband communications to spectroscopy and nonlinear control of materials. Future progress in THz technology depends on the…

Two-dimensional graphene plasmon-based technologies will enable the development of fast, compact and inexpensive active photonic elements because, unlike plasmons in other materials, graphene plasmons can be tuned via the doping level. Such…

Mesoscale and Nanoscale Physics · Physics 2016-02-20 S. Chakraborty , O. P. Marshall , T. G. Folland , Y. -J. Kim , A. N. Grigorenko , K. S. Novoselov

Room temperature Terahertz stimulated emission and population inversion in optically pumped graphene is reported. We experimentally observe fast relaxation and relatively slow recombination dynamics of photogenerated electrons/holes in an…

Materials Science · Physics 2012-08-27 Stephane Boubanga Tombet , Silvia Chan , Taiichi Otsuji , Akira Satou , and Victor Ryzhii

We report on the frequency conversions of terahertz (THz) waves at ultrafast time boundaries created via femtosecond laser-induced air-to-plasma phase transitions. Our combined experimental and theoretical approach reveals that the abrupt…

The lateral interdigital array of the graphene microribbons (GMRs) on the h-BN substrate connected by narrow graphene nanoribbon (GNR) bridges serves as an efficient detector of terahertz (THz) radiation. The detection is enabled by the…

Mesoscale and Nanoscale Physics · Physics 2024-11-13 V. Ryzhii , C. Tang , T. Otsuji , M. Ryzhii , M. S. Shur

Terahertz quantum cascade lasers (THz QCLs) are chip-scale semiconductor lasers operating in the frequency range between 1-6 THz, useful as compact sources for spectroscopy, communications, and non-destructive imaging and testing. Here, we…

Real-time measurement of the absolute frequency of continuous-wave terahertz (CW-THz) waves is required for characterization and frequency calibration of practical CW-THz sources. We proposed a method for real-time monitoring of the…

We report on experimental studies of terahertz (THz) radiation transmission through grating-gate graphene-channel transistor nanostructures and demonstrate room temperature THz radiation amplification stimulated by current-driven plasmon…