Waves In Two-dimensional Plasma Research Articles

TeraHertz electronic noise in field-effect transistors

We present a theoretical investigation of high-frequency electronic noise in field-effect transistors used as detectors of TeraHertz radiation. Calculations are performed using the hydrodynamic-Langevin approach and specialized to the case of InGaAs high-electron mobility transistors. The main physical phenomena associated with the effect of branching of the total current between channel and gate and the appearance of two-dimensional plasma waves are discussed. We demonstrate that thermally excited standing plasma waves originate series of resonant peaks in the corresponding noise spectral densities whose presence can be controlled by the embedding circuit. A significant damping of the high-frequency excess noise is found when the transistor is submitted to a two-lasers optical photo-excitation presenting a beating frequency in the TeraHertz range. Finally, we discuss the dependence of the damping effect, as well as a shift of the resonance peaks from the presence of channel ungated regions.

THz Emission Induced by an Optical Beating in Nanometer-Length High-Electron-Mobility Transistors

Experimental results of direct measurement of resonant terahertz emission optically excited in InGaAs HEMT channels are presented. The emission was attributed to two-dimensional plasma waves excited by photogeneration of electron–hole pairs in the HEMT channel at the frequency of the beating of two cw-laser sources. The presence of resonances for the radiation emission in the range of f0±10 GHz (with f0 from 0.3 up to 0.5 THz) detected by a Si-bolometer is found. The intensity of THz emission exhibits a nonlinear growth with increase of the pumping power.

Oblique interactions between multi-solitons in plasma

The nonlinear waves in two-dimensional plasma are studied in this paper. Solitary waves propagating in two different directions are investigated as well. The equation of motion of nonlinear wave in the different directions is also obtained. The phase shifts after the interaction for multi-solitons in different directions are given in the present work.

Nonlinear waves in twirling plasmas

AbstractThe dynamics of nonlinear two-dimensional plasma waves under non-equilibrium conditions is studied in the framework of the two-fluid hydrodynamic approach. The field of initial velocities for a twirling cylindrical plasma is considered as the initial non-equilibrium state. The influence of initial conditions on the formation and existence of nonlinear electron waves is discussed.

Propagation and Interaction of Ion-Acoustic Solitary Waves in a Two-Dimensional Plasma Consisting of Isothermal Electrons and Hot Ions

We study the propagation and interaction of ion-acoustic solitary waves in a simple two-dimensional plasma by using the extended Poincaré–Lighthill–Kuo perturbation method. We consider the interaction between two ion-acoustic solitary waves with different propagation directions in such a system, and obtain two Korteweg-de Vries equations for small but finite amplitude solitary waves along both ξ and η trajectories. The effects of the ratio of ion temperature σ, the ratio of heat capacity γ and the colliding angle α. on the amplitude, the width of the new nonlinear wave created by the collision between two solitary waves are studied. The effects of these parameters on both the colliding solitary waves are examined as well. It is found that all the above-mentioned parameters have significant effects on the properties of these nonlinear waves.

ERRATA: "THz DETECTION BY RESONANT 2-D PLASMONS IN FIELD EFFECT DEVICES"

We demonstrate resonant detection of terahertz radiation by two-dimensional plasma waves in two field effect devices: a commercial field effect transistor (FET) and a double quantum well field effect transistor with a periodic grating gate. In both devices, the standing 2-D plasmon is tuned to the frequency of the THz radiation by varying the gate bias. The double quantum well field effect transistors exhibits a rich photoconductive response corresponding to spatial harmonics of the standing 2-D plasmons under the metal part of the periodic gate.

Generation of submillimeter electromagnetic radiation from two-dimensional plasma waves in a semiconductor heterostructure with metal grating

The effect of the stimulated coherent emission of electromagnetic radiation from a semiconductor periodic microstructure with drifting two-dimensional electron plasma is theoretically studied. The physical mechanism and criterion for the development of the absolute instability in the system is discussed. The gap in the threshold region of drift velocities is found.

Potential inversion of the two-dimensional plasma wave equation

A layer-stripping-type method is developed for solving an inverse problem for the two-dimensional plasma wave equation where the object is to find the potential given the normal derivative of the plasma wave, measured along the boundary of a half-space. The key point of the method is that we use one-way wave approximation equations instead of the full wave equation for extrapolation of the wave field to avoid instability in numerical computation. Numerical experiments are performed on some simple examples to examine the effectiveness of the method.

Plasmon excitation by coulomb scattering of electrons in 2D systems

We report new far infrared emission experiments from radiative decay of two-dimensional plasma waves. The excitation is generated by a heating of the electron gas in the applied electric field. Local fluctuations of the charge density require for plasma wave excitation an additional momentum exchange, which is provided by Coulomb scattering. For the first time radiative decay of magnetoplasmon excitations is studied. The intensity drastically decreases with magnetic field, the dispersion of the magnetoplasmon agrees with theory up to magnetic fields of 3.5 Tesla.