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Graphene based plasma-wave devices for terahertz applications
摘要： Unique properties of graphene are combined to enable graphene plasmonic devices that could revolutionize the terahertz (THz) electronic technology. A high value of the carrier mobility allows us to excite resonant plasma waves. The graphene bipolar nature allows for different mechanisms of plasma wave excitation. Graphene bilayer and multilayer structures make possible improved THz device configurations. The ability of graphene to form a high quality heterostructure with h-BN, black phosphorus, and other materials systems supports advanced heterostructure devices comprised of the best properties of graphene and other emerging materials. In particular, using black phosphorus compounds for cooling electron–hole plasma in graphene could dramatically improve the conditions for THz lasing. High optical phonon energy allows for reaching higher plasma frequencies that are supported by high sheet carrier densities in graphene. Recent improvements in graphene technology combined with a better understanding of the device physics of graphene THz plasmonics and graphene plasmonic device designs hold promise to make graphene THz plasmonic technology one of the key graphene applications. Commercialization of plasmonic graphene technology is facing the same challenges as other graphene applications, which have difficulties in producing uniform large graphene layers, bilayers, and heterostructures of high quality and making good low resistance stable Ohmic contacts. The time projection for large scale graphene electronic device applications now extends into the 2030s. However, emerging graphene mass production technologies might bring commercial applications of the graphene plasmonic terahertz technology closer.
关键词： heterostructures,graphene,black phosphorus,Ohmic contacts,plasma waves,THz technology,terahertz,plasmonic devices,optical phonon energy,carrier mobility
更新于2025-09-19 17:13:59
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Nonlinear plasma wavelength scalings in a laser wakefield accelerator
摘要： Laser wake?eld acceleration relies on the excitation of a plasma wave due to the ponderomotive force of an intense laser pulse. However, plasma wave trains in the wake of the laser have scarcely been studied directly in experiments. Here we use few-cycle shadowgraphy in conjunction with interferometry to quantify plasma waves excited by the laser within the density range of GeV-scale accelerators, i.e., a few 1018 cm?3. While analytical models suggest a clear dependency between the nonlinear plasma wavelength and the peak potential a0, our study shows that the analytical models are only accurate for driver strength a0 (cid:2) 1. Experimental data and systematic particle-in-cell simulations reveal that nonlinear lengthening of the plasma wave train depends not solely on the laser peak intensity but also on the waist of the focal spot.
关键词： nonlinear plasma wavelength,particle-in-cell simulations,plasma waves,laser wake?eld acceleration
更新于2025-09-16 10:30:52
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Interactions of laser speckles due to kinetic stimulated Raman scattering
摘要： We examine the possible interactions of two laser speckles due to the exchange of electrons and waves generated by stimulated Raman scattering (SRS) using two-dimensional particle-in-cell simulations. By controlling the relative polarization, spatial placement, and timing of two laser speckles, one above-threshold and one below-threshold for SRS, we isolate and characterize SRS growth stimulated in below-threshold speckles. SRS in the below-threshold speckle is shown to be triggered by energetic electrons, scattered light waves, and scattered plasma waves generated from the above-threshold speckle. We show that scattered light or electrons alone can be an intermediary trigger for SRS.
关键词： electron plasma waves,particle-in-cell simulations,stimulated Raman scattering,laser speckles
更新于2025-09-12 10:27:22
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High power THz-range Wave generation based on Transformation of Plasma Waves Pumped by High-current Relativistic Electron Beam
摘要： The beam-plasma interaction system allows one to generate high-power sub-mm waves (frequency interval 0.1÷1 THz) by usage of mechanism of plasma wave transformation [1]. This way gives possibility to achieve multi megawatt power with the promptly varying frequency that can be necessary for various practical applications. The original project of a sub-mm wave based on transformation of plasma waves pumped by a kA-current relativistic electron beam is developed at the GOL-PET facility. We present novel results on the study of mechanisms of sub-mm wave emission by the processes of plasma wave transformation in electromagnetic one in case of the strong beam-plasma interaction.
关键词： sub-mm wave generation,plasma waves,beam-plasma interaction,relativistic electron beam,THz-range
更新于2025-09-10 09:29:36
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The instability of terahertz plasma waves in cylindrical FET
摘要： In this paper, the Dyakonov-Shur instability of terahertz (THz) plasma waves has been analyzed in gated cylindrical ?eld effect transistor (FET). In the cylindrical FET, the hydrodynamic equations in cylindrical coordinates are used to describe the THz plasma wave in two-dimensional electronic gas. The research results show that the oscillation frequency of the THz plasma wave is increased by increasing the component of wave in the circumferential direction, but instability increment of the THz plasma wave are increased by increasing the radius of channel.
关键词： oscillation frequency,cylindrical ?eld effect transistor,THz plasma waves
更新于2025-09-04 15:30:14