A. D. Gladun

Backward waves in planar insulator?metal?insulator waveguide structures

Existence conditions of backward waves and waves with zero group velocity in insulator–metal–insulator (IMI) structures are obtained and expressions for the group velocity of the surface plasmon polariton (SPP) are derived. We consider the general case when the two insulator half-spaces may be identical or different. The effect of losses on dispersion curves and values of the energy velocity is analyzed. The obtained equations are used for a characterization and a detailed study of backward waves in thin silver film waveguides.

Detection of Modulated Terahertz Radiation Using Combined Plasma and Mechanical Resonances in Double-Carbon-Nanotube Device

We propose a resonant detector of terahertz radiation modulated by megahertz or gigahertz signals. The detector is based on mechanically floating carbon nanotubes (CNTs), suspended over an insulator. The device operation is associated with the excitation of both plasma and mechanical oscillations in CNTs resulting in an ac displacement current between them. This current plays the role of the detector output signal. Using the proposed device model, we find that the frequency dependence of the detector responsivity exhibits a sharp peak at the combined plasma-mechanical resonance and estimate its maximum value.

Parametric instability in a nanoelectromechanical detector of modulated terahertz radiation on the basis of a high electron mobility transistor with a mobile elastic gate

Parametric instability in a modulated terahertz radiation detector based on a high electron mobility transistor with a mobile elastic gate fabricated from a conductor in the form of a micronanocantilever is studied in detail. The analysis is based on the method of coupled oscillations and subsequent testing by direct numerical integration of the original equations. The thresholds and increments of the instability are determined. The feasibility of practical realization of conditions for parametric instability in such detectors is discussed.

Plasma oscillations of the two-dimensional electron gas in the field-effect transistor with a cylindrical gate electrode

The frequency characteristics of the two-dimensional electron gas in the field-effect transistor with with a cylindrical gate electrode are obtained in the framework of the linear hydrodynamic model. The effect of the transverse dimension and the position of the gate electrode and the parameters of thetwo-dimensional electron gas layer on the resonance characteristics of the field-effect transistor is analyzed. The practical prospects of the results in the development of nanosized oscillators and detectors of the terahertz electromagnetic radiation are outlined.

Carbon nanotube based resonant detector of modulated terahertz radiation

A system of two freely suspended single-walled carbon nanotubes in the form of a segment of a transmission line is considered. Its electrodynamic description is based on the Tomonaga-Luttinger liquid model. The system under investigation is a plasmon resonator with a resonance frequency from the terahertz range, which serves as a high-Q mechanical oscillator coupled with the plasmon resonator by a nonlinear ponderomotive force. As a possible application of this system, a new model of resonant detector is proposed. The output parameters of such a nanosized detector are obtained.

Parametric instability in the resonance detector of terahertz radiation based on FET with cylindrical gate electrode

A possibility of the parametric instability in the resonance detector of the modulated terahertz radiation is analyzed. The detector represents a system of capacitively coupled plasma and mechanical resonators. A layer of 2D electron gas with a relatively high electron mobility and a cylindrical gate electrode that is fixed at the ends serve as the first and second resonators, respectively. The method of coupled oscillations is used to obtain the dependence of the minimum threshold pump power of the plasma circuit that corresponds to the excitation of the parametric instability on the main geometrical and electric parameters of the system.

Detection of ultrashort pulses with a plasmonic nanocavity based on the insulator-insulator-metal waveguide

We propose a novel technique of detection of ultrashort and few-cycle light pulses with a plasmonic nanocavity that is based on the extremely-slow-energy-velocity mode of the insulator-insulator-metal waveguide. We characterize the cavity analytically and demonstrate how it works using the FDTD method.

Parametric instability of mobile elastic gate in tera- and nano- high electron mobility transistor

Effective excitation of the micro- and nanometer-size resonators has number of applications at various fields of science and technology. In particular, they include wireless telecommunication technologies [1], high sensitivity measuring systems [2], quantum information processing devices [3]. At the present report we consider the mechanical cantilever oscillations parametric excitation that serves as the gate electrode of a high electron mobility transistor (HEMT). The parametric coupling between the mechanical resonator (cantilever) and the oscillations of two-dimensional electron gas (2DEG) with high electron mobility is considered. In the capacity of the mechanical resonator a clamped nanobeam or a carbon nanotube might be used. 2DEG can arise in GaAs/AlGaAs heterostructures on the basis of which high electron mobility transistors (HEMT) are produced. Previously number of authors investigated the influence of the parametric coupling between mechanical and optical resonators [4, 5]. At our recent work [6] we proposed the uniform approach to such problems that is based on the lumped parameters method and the reduction of the parametric instability occurrence conditions question to the pure mathematical problem or the numerical solution of the certain system of second-order ODEs.

Nanomechanical systems with plasmonic resonances as detectors of modulated terahertz radiation

Our nanomechanical system reveals both the mechanical resonance associated with the mechanical oscillations of the nanocantilever and the plasma resonances due to the surface plasmons. The system in question can exhibit a gigantic response (very high sensitivity) when the modulation and carrier frequencies coincide with the mechanical and plasma resonant frequencies, respectively [1, 2]. Relatively large amplitude of the nanocantilever mechanical oscillations under the effect of the averaged field at the combined resonance results in relatively strong displacement ac current between the nanocantilever and the metal surface. This ac current at the modulation frequency can serve as the detector output signal.

A method to increase the Arctic sea ice cover

Proposed in this paper is a new method for preserving the ice in the Arctic regions under the conditions of global warming. The main technique involves artificial polymer films, which are used as an additional cover for the overcooled northern regions. The polymer films are constructed in such a way that they cannot only reflect the incoming solar radiation but also provide additional sites for the nucleation of ice crystals. This feature of polymer films to produce ice crystal aggregation in the larger ice structures in the adjoining area can be achieved by decreasing sea wave amplitudes in the vicinity of the considered area.