Collinear interaction of optical waveguide modes with an increasing space-charge wave

Collinear interaction of optical modes in a thin-film semiconductor waveguide with a space-charge wave increasing along its propagation direction has been investigated. Analytical solutions to the equations of coupled unidirectional and counterpropagating waveguide modes at their phase matching are obtained for the first time, and the dependence of the mode conversion efficiency on the space-charge wave amplification level, the coupling coefficient, and the length of the interaction region of optical modes is analyzed.     

New model describing interaction between an electromagnetic wave and a molecule

The expediency of refining some basic concepts of the common theory of interaction between an electromagnetic field and a substance using a quasi-classical model for the phenomena of absorption and emission of energy and Raman scattering (RS) is considered. The use of the time-dependent Schrodinger equation for obtaining the transition probability constants is discussed. A new model that describes the intensities of the RS lines and involves the explicit introduction of the perturbation operator for the RS spectrum is proposed. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 309–318, May–June, 2008.     

Waveguide interaction of light with spin waves in a ferromagnetic film

We discuss the results of a theoretical analysis of the waveguide interaction of light and spin waves. Both linear and quadratic magnetooptical effects are taken into account. The features of the interaction are considered for the three principal types of spin waves: waves in a normally magnetized ferromagnetic film, and longitudinal and transverse waves in a tangentially magnetized film. Isotropic and anisotropic diffraction processes are considered. Numerical estimates of the intensity and frequency properties of the diffraction scattering are given for a number of situations of practical interest. The effect of a strong constant magnetic field on the interaction of light and spin waves is considered.Translated from Izvestiya Vyssnikh Uchebnykh Zavednii, Fizika, No. 4, pp. 5–31, April, 1989.     

Frequency characteristics and spatial intensity distribution of light generated and amplified by parametric three-photon interaction

The distribution of frequency and intensity over the beam cross section was measured for radiation generated by single-path parametric amplification (three-photon interaction) in KDP (Type II phasematching). The results agree well with theoretical predictions.     

An approximate two-dimensional theory of interaction between an electron beam and an electromagnetic wave (noise- and photo-traveling wave tubes)

Processes that occur in a traveling wave tube(TWT) equipped with a photocathode are examined within two-dimensional theory. The impact of noise fluctuations of the beam is studied, and the dependences of the amplifier’s noise factor are obtained. The interaction between an electromagnetic wave with an infinitely thin strip electron beam is described with allowance for a finite focusing magnetic field and the space charge field.     

Electromagnetic interaction between local surface plasmon polaritons and an atmospheric surface wave plasma jet

We analyze the electromagnetic interaction between local surface plasmon polaritons （SPPs） and an atmospheric surface wave plasma jet （ASWPJ） in combination with our designed discharge device. Before discharge, the excitation of the SPPs and the spatial distribution of the enhanced electric field are analyzed. During discharge, the critical breakdown electric field of the gases at atmospheric gas pressure and the surface wave of the SPPs converted into electron plasma waves at resonant points are studied. After discharge, the ionization development process of the ASWPJ is simulated using a two- dimensional fluid model. Our results suggest that the local enhanced electric field of SPPs is merely the precondition of gas breakdown, and the key mechanism in maintaining the discharge development of a low-power ASWPJ is the wave-mode conversion of the local enhanced electric field at the resonant point.     

Resonant interaction between excitons and intense coherent light

Starting from a Hamiltonian which describes the interaction of the many-electron system of a crystal with the quantized light field, we derive a set of nonlinear wave-equations for the field and exciton amplitude and the exciton occupation number. Our treatment comprises both Frenkel and Wannier excitons. Our equations form a sound basis for treating both pulse-propagation phenomena and giant polaritons in crystals.     

Parametric interaction of space-charge waves in thin-film semiconductor structures

The general theory of parametric coupling between space-charge waves and drifting charge carriers in thin-film semiconductor structures has been worked out. This theory is applicable, in particular, to n-GaAs and n-InP semiconductors with negative differential conductance due to intervalley electron transitions under high electric fields. We started from the electrodynamic theory of waveguide excitation by extraneous currents, which was extended for arbitrary waveguide structures with composite active media. Our theory makes it possible to study parametric interaction between space-charge waves in semiconductor films with regard for boundary conditions, diffusion, the anisotropy and the frequency dispersion of the differential electron mobility, as well as the multifrequency and multimode nature of a wave process in thin-film structures.     

The theory of interaction between wave and basic flow

This paper investigates the interaction between transient wave and non-stationary and non-conservative basic flow. An interaction equation is derived from the zonally symmetric and non-hydrostatic primitive equations in Cartesian coordinates by using the Momentum-Casimir method. In the derivation, it is assumed that the transient disturbances satisfy the linear perturbation equations and the basic states are non-conservative and slowly vary in time and space. The diabatic heating composed of basic-state heating and perturbation heating is also introduced. Since the theory of wave-flow interaction is constructed in non-hydrostatic and ageostrophic dynamical framework, it is applicable to diagnosing the interaction between the meso-scale convective system in front and the background flow.
It follows from the local interaction equation that the local tendency of pseudomomentum wave-activity density depends on the combination of the perturbation flux divergence second-order in disturbance amplitude, the local change of basic-state pseudomomentum density, the basic-state flux divergence and the forcing effect of diabatic heating. Furthermore, the tendency of pseudomomentum wave-activity density is opposite to that of basic-state pseudomomentum density. The globally integrated basic-state pseudomomentum equation and wave-activity equation reveal that the global development of basic-state pseudomomentum is only dominated by the basic-state diabatic heating while it is the forcing effect of total diabatic heating from which the global evolution of pseudomomentum wave activity results. Therefore, the interaction between the transient wave and the non-stationary and non-conservative basic flow is realized in virtue of the basic-state diabatic heating.     

Soliton interaction with an external traveling wave

The dynamics of soliton pulses in the nonlinear Schrodinger equation (NLSE) driven by an external traveling wave is studied analytically and numerically. The Hamiltonian structure of the system is used to show that, in the adiabatic approximation for a single soliton, the problem is integrable despite the large number of degrees of freedom. Fixed points of the system are found, and their linear stability is investigated. The fixed points correspond to a Doppler shifted resonance between the external wave and the soliton. The structure and topological changes of the phase space of the soliton parameters as functions of the strength of coupling are investigated. A physical derivation of the driven NLSE is given in the context of optical pulse propagation in asymmetric, twin-core optical fibers. The results can be applied to soliton stabilization and amplification.     

Multiparticle entanglement via resonant interaction between light and atomic ensembles

Multiparticle entangled states generated via interaction between narrowband light and an ensemble of identical two-level atoms are considered. Depending on the initial photon statistics, correlation between atoms and photons can give rise to entangled states of these systems. It is found that the state of any pair of atoms interacting with weak single-mode squeezed light is inseparable and robust against decay. Optical schemes for preparing entangled states of atomic ensembles by projective measurement are described.     

Resonant interaction between a localized fast wave and a slow wave with constant asymptotic amplitude

An integrable Yajima-Oikawa system is solved in the case of a finite density, which corresponds to a slowly varying (long-wavelength) wave with finite amplitude at infinity and a localized fast-oscillating (short-wavelength) wave. Application of the results to spinor Bose-Einstein condensates and other physical systems is discussed.     

Stokes parameters of an electromagnetic light wave on scattering

Stokes parameters of an electromagnetic light wave on scattering have been discussed, which permit us to study the spectral degree of polarization of the far-zone scattered field. An example of scattering of a spatially coherent electromagnetic light wave from a quasi-homogeneous medium has been discussed to illustrate the changes of the Stokes parameters and the changes of the spectral degree of polarization of the far-zone scattered field.     

Resonant interaction of an electromagnetic wave with an inhomogeneous plasma slab

Resonant interaction at oblique incidence of an electromagnetic wave on an inhomogeneous plasma slab is studied. The time evolution of this interaction is solved numerically from two-fluid equations, adiabatic equation for electron pressure and from Maxwell equations. It is shown that the electromagnetic energy of an incident wave is transformed both into the heat energy and into the energy of plasma oscillations in the direction of density gradient. The distribution of the transformed energy between the heat energy and the energy of plasma oscillations is strongly dependent on the plasma temperature. The ratio of heat energy to the energy of plasma oscillations is growing with growing temperature. The plasma oscillations are generated by magnetic induction of the penetrating wave. In a cold plasma they are generated especially in the overdense region and their frequency is equal to local plasma frequency. The electric field in the direction of plasma gradient has a form of a wave packet whose envelope reaches a maximum at resonance. The characteristic wavelength in the wave packet decreases and the amplitude of the packet increases with the time.     

Nonlinear analysis of interaction between multispiral electron fluxes and electromagnetic wave

The interaction of a circularly polarized plane electromagnetic wave with a multispiral electron flux in the presence of an external magnetic field is considered. It is shown that under certain conditions it is possible to transform the electron-flux energy into wavefield energy as a result of the dependence between the rotational and translational motion of the particles.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 87–91, October, 1978.     

Nolinear interaction between P-and SV-wave in isotropic elastic media

I.IntroductionInthelinearwavethcory,thestressinaso1idisproportionaltostrainsandthepropagatingwaves(suchasP-,SV-andSH-waves)satisfythehomogeneouswaveequation.Iftherearesomeboundaries,thereflectionandrefractionobeytheSne11'sla.[1l.Inthenon1inearmcdia,ontheotherhand,a11theequationsarenon1inearsoitisverydifficulttoobtainanexactsolu-honingeneral.Usua11y,thepcrturbationmethodsarcinvokedtofindanapproximateso1ution.Sincethenon1ineartermsofthestrainsappearinthestrcsses,two-waveinteractionwilltakep1…