Anisotropic spin—lattice relaxation in the triplet state of naphtralene-h8 in n-pentane

The temperature dependence of the individual spin—lattice relaxation rate constants (W_ij) between the lowest triplet sublevels of naphthalene-h₈ in a polycrystalline Shpol'skii matrix of n-pentane have been measured between 1.2 and 2.4 K in zero field. The total sublevel decay constants are evaluated and found to be independent of temperature. The W_ij are found to be highly anisotropic, but the anisotropy pattern differs from that observed previously in a durene matrix.     

Electromagnetic wave propagation from a point source in air through a medium with a negative refractive index

Refraction of an electromagnetic wave from a point source to a medium with a negative refractive index is considered. An electric Hertz dipole that is located in air and directed parallel to a plane interface is considered as the point source. It is rigorously shown that the electromagnetic radiation propagated from the dipole into the medium with the negative refractive index is focused within a certain region in this medium. The sizes of the focusing region are determined. As a result, it is pointed out that the diffraction limit cannot be overcome by using homogeneous materials with negative refractive indices.     

An Elementary Dipole Emitter Located Either on the Boundary of a Layered Structure or Inside It

Optics and Spectroscopy - A rigorous theory of radiation of an elementary dipole that is located either on the boundary of a plane-layered structure or inside it is considered. For a particular...     

On the Theory of a Flat Lens from a Material with Negative Refraction

Optics and Spectroscopy - A rigorous theory of the propagation of an electromagnetic wave that is emitted by a point elementary current source and that is focused by a flat layer filled with a...     

On the Electron Emission from the Focal Region of a Symmetrically Convergent Surface Plasmonic Wave on the Free Surface of a Metal Film

Optics and Spectroscopy - Excitation and focusing of a radially convergent surface plasmonic wave on the free surface of a gold film in the Kretschmann geometry have been considered based on the...     

Elementary Emitter at the Boundary of a Flat-Layered Structure

Journal of Experimental and Theoretical Physics - A rigorous theory of emission of an elementary dipole located at the boundary of or within a flat-layered structure has been considered. A method...     

Hysteresis in the presence of electron-cyclotron resonance

A method of determining the nonlinear interaction of microwaves with a magnetoactive lowpressure plasma is presented. It is shown by solving simultaneously the problems of the propagation of electromagnetic waves, the balance of charged particles, and the energy balance that near a critical value of the constant magnetic induction the character of the interaction of the wave and the plasma changes substantially: For magnetic fields above the critical field a much stronger interaction is observed, for which the penetration depth of the incident wave into the plasma increases. An investigation of the strong interaction regime showed the existence of hysteresis, which is accompanied by an abrupt transition from one standing-wave mode in plasma to another. It is shown that virtually complete absorption of the wave is possible. Zh. Tekh. Fiz. 69, 31–37 (December 1999)     

Transmission of microwaves through magnetoactive plasma

The possibility of transmission of microwaves through the plasma layer with an electron concentration of more than critical value is considered. The problem is solved by consideration of the interaction of a microwave with the plane layer of magnetoactive plasma. The problem is formulated by such a way as to obtain the estimation of the greatest lower bound of microwave transmission coefficient through the plasma layer. The results of numerical parametric investigations are applied for the transparency conditions of the shock wave plasma in space communication. The possibility of stable (without interruptions) microwave communication through the shock wave plasma is demonstrated     

A point radiator parallel to a plane layer with negative refractive index

Focusing of an electromagnetic wave radiated by a point source and transmitted through a plane layer filled with a medium with negative refractive index is considered. An elementary electric Hertzian dipole located in the air (or vacuum) parallel to the boundaries of the layer is considered as a point source of radiation. It is rigorously shown that, after transmitting through a layer with negative refractive index, the electromagnetic wave of the dipole is focused into a certain domain. The dimensions of the focusing region are investigated. The results of the investigation show that the use of homogeneous materials with negative refraction does not allow one to overcome the diffraction limit.     

Nonlinear interaction of microwave and plane magnetoactive plasmalayer

A method for calculating the interaction of a microwave with a plane layer of magnetoactive low-pressure plasma is presented. In this paper, the plasma layer is situated between a plane dielectric layer and a plane metal screen. The calculation model contains the microwave energy balance, particle balance, and electron energy balance. The numerical calculations of the nonlinear interaction of the incident plane microwave and the plane plasma layer show that there are hysteresis phenomena when the intensity of the incident microwave is changed. The cause of these hysteresis phenomena is considered. As a result of this investigation, the conditions of effective power transfer from the microwave to the plasma have been found