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Terahertz emission by the photon-assisted resonant radiative transitions between graphene layers (GLs) in double-GL structures is theoretically and experimental demonstrated. Devices such as terahertz/infrared lasers base on this technology are very promising for terahertz optoelectronics.
We report on the intrinsic responsivity of an asymmetric dual-grating-gate plasmonic detector over 100 kV/W at 200 GHz and 50 kV/W at 300 GHz measured at room temperature with zero source-drain bias. We demonstrate that broadband characteristics of the responsivity depend much on the geometrical parameters of the detectors.
Double-graphene-layer (DGL) heterostructures have recently attracted much attention due to their potential applications in high speed modulators of terahertz (THz) and infrared (IR) radiation, transistors, and THz photomixers [1]. In this work we report experimental observation of THz emission and detection in the DGL device structures. We demonstrate that the photon-assisted resonant radiative inter-GL...
This paper reviews recent advances in graphene plasmonic heterostructures for terahertz (THz) device applications. A double graphene-layer (DGL) core-shell structure with a tunnel-barrier layer is sandwiched between the outer gate stack layers at both sides. When the band offset is aligned to the THz photon energy, the DGL structure can mediate photon-assisted resonant tunneling, resulting in resonant...
We use ultrafast optical microscopy to investigate carrier dynamics in single flakes of atomically thin molybdenum disulfide. By tuning the probe wavelength through the bandgap, we reveal the influence of layer thickness on carrier dynamics.
This paper reports on emission and detection of terahertz radiation using two dimensional (2D) plasmons in semiconductor nano-heterostructures for sensing applications. The device structure is based on a high-electron mobility transistor and incorporates the authors' original asymmetrically interdigitated dual-grating gates. Excellent terahertz emission and detection performances are experimentally...
This paper reviews recent advances in ultrafast and ultrahigh sensitive broadband terahertz detection utilizsing asymmetric double-grating-gate InP-based high-electron-mobility transistors, demonstrating a record responsivity of 2.2 kV/W at 1 THz under drain-unbiased conditions with a superior low noise equivalent power of 15 pW/√Hz and 6.4 kV/W even at 1.5 THz under drain-biased conditions.
Double-grating-gate field-effect transistors have a great potential as terahertz detectors. The double grating gate serves not only for carrier density tuning but also as an efficient THz radiation coupler. Low and high magnetic field detection results are used to determine the electron mobility and electron concentration, respectively, in the different parts of the channel.
We report terahertz detectors with a record sensitivity of 6.4 kV/W and noise equivalent power of 15 pW/√Hz in the above 1 THz region. The key point of this major breakthrough is careful design and fabrication of Plasmonic devices based on Field Effect Transistor structures combining interdigitated metal gates and an asymmetric metallization scheme.
The development of Terahertz optoelectronic devices is a subarea of major currently ongoing advanced research effort. Electronic and photonic solidstate devices reache fundamental limitations in Terahertz frequency range, therefore this development is very crucially relying on the availability of new materials, new physical mechanisms, new device designs, and new fabrications/approaches. Here we explore...
We report on reflective electro-optic sampling measurements of TeraHertz emission from nanometer-gate-length InGaAs-based high electron mobility transistors. The room temperature coherent gate-voltage tunable emission is demonstrated. Our results shows that properly exciting nanotransistors can pave the way for new class of coherent and easily tunable THz sources.
The gapless and linear energy spectra of electrons and holes in graphene lead to nontrivial features such as negative dynamic conductivity in the terahertz spectral range. This paper reviews the recent advances in theoretical and experimental study on terahertz light amplification by stimulated emission of radiation in optically pumped graphene.
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