Search results for "PROPAGATION"
showing 10 items of 676 documents
Vectorial Kerr-cavity solitons.
2000
It is shown that a Kerr cavity with different losses for the two polarization components of the field can support both dark and bright cavity solitons (CS’s). A parametrically driven Ginzburg–Landau equation is shown to describe the system for large-cavity anisotropy. In one transverse dimension the nonlinear dynamics of the bright CS’s is numerically investigated.
Higher-order Kerr effect in ultrashort laser pulse propagation and laser filamentation
2011
We discuss the contribution of the higher-order Kerr effect (HOKE) to the propagation of ultrashort laser pulses in several contexts. We show that their consideration is necessary to adequately reproduce experimental data about harmonics generation, propagation in hollow-core fibers, and laser filamentation. In the latter case, our results show that the HOKE play a key role for short pluses and/or long wavelengths, while the plasma contributes more for long pulses and/or short wavelengths.
Coherent potential approximation for diffusion and wave propagation in topologically disordered systems
2013
Using Gaussian integral transform techniques borrowed from functional-integral field theory and the replica trick we derive a version of the coherent-potential approximation (CPA) suited for describing ($i$) the diffusive (hopping) motion of classical particles in a random environment and ($ii$) the vibrational properties of materials with spatially fluctuating elastic coefficients in topologically disordered materials. The effective medium in the present version of the CPA is not a lattice but a homogeneous and isotropic medium, representing an amorphous material on a mesoscopic scale. The transition from a frequency-independent to a frequency-dependent diffusivity (conductivity) is shown …
Strong four-photon conversion regime of cross-phase-modulation-induced modulational instability
2000
We investigate theoretically and experimentally the strong conversion regime of parametric four-photon amplification or induced modulational instability in the normal dispersion regime of propagation in a highly birefringent fiber. Such optical mixing is observed by injecting a tunable linearly polarized (along the fast axis) anti-Stokes signal wave copropagating with a pump equisplitted between the fiber axes (i.e., linearly polarized at 45\ifmmode^\circ\else\textdegree\fi{}) which entail that the two pump modes experience cross-phase modulation. In agreement with a four-wave model developed to study the depleted regime of the mixing process, we observe that the strongest conversion occurs…
Switching Reciprocity On and Off in a Magneto-Optical X-Ray Scattering Experiment Using Nuclear Resonance ofα−Fe57Foils
2012
Reciprocity is when the scattering amplitude of wave propagation satisfies a symmetry property, connecting a scattering process with an appropriate reversed one. We report on an experiment using nuclear resonance scattering of synchrotron radiation, which demonstrates that magneto-optical materials do not necessarily violate reciprocity. The setting enables us to switch easily between reciprocity and its violation. In the latter case, the exhibited reciprocity violation is orders of magnitude larger than achieved by previous wave scattering experiments.
Elastic waves propagation in 1D fractional non-local continuum
2008
Aim of this paper is the study of waves propagation in a fractional, non-local 1D elastic continuum. The non-local effects are modeled introducing long-range central body interactions applied to the centroids of the infinitesimal volume elements of the continuum. These non-local interactions are proportional to a proper attenuation function and to the relative displacements between non-adjacent elements. It is shown that, assuming a power-law attenuation function, the governing equation of the elastic waves in the unbounded domain, is ruled by a Marchaud-type fractional differential equation. Wave propagation in bounded domain instead involves only the integral part of the Marchaud fraction…
Oscillations of a highly discrete breather with a critical regime
2000
We analyze carefully the essential features of the dynamics of a stationary discrete breather in the ultimate degree of energy localization in a nonlinear Klein-Gordon lattice with an on-site double-well potential. We demonstrate the existence of three different regimes of oscillatory motion in the breather dynamics, which are closely related to the motion of the central particle in an effective potential having two nondegenerate wells. In given parameter regions, we observe an untrapped regime, in which the central particle executes large-amplitude oscillations from one to the other side of the potential barrier. In other parameter regions, we find the trapped regime, in which the central …
Ansatz independent solution of a soliton in a strong dispersion-management system
2001
We introduce a theoretical approach to the study of propagation in systems with periodic strongmanagement dispersion. Our approach does not assume any ansatz about the form of the solution nor does it make use of any average procedure. We find an explicit solution for the pulse evolution in the fast dynamics regime ~distances smaller than the dispersion period!. We also establish the equation of motion governing the slow dynamics of an arbitrary pulse and prove that the pulse evolution is nonlinear and Hamiltonian. We solve this equation and find that a nonlinear solitonlike solution occurs self-consistently in the form of an asymptotic stationary eigenfunction of the Hamiltonian.
Wave Modulations in the Nonlinear Biinductance Transmission Line
2001
Adding dissipative elements to a discrete biinductance transmission line which admits both low frequency (LF) and high frequency (HF) modes, dynamics of a weakly nonlinear modulated wave is investi...
Efficient control of the energy exchange due to the Manakov vector-soliton collision
2003
By examining the concept of energy exchange among the orthogonally polarized components of each of two colliding (Manakov-like) vector solitons it is observed that a maximum or an efficient energy-exchange process is possible only for an appropriate choice of the initial physical parameters (namely, frequency separation, polarizations, time delay, and pulse-width separation between the colliding solitons) for which L(W) (walk-off length) >>L(NL) (nonlinear length). However, in this case only, the amount of energy-exchange can be considerably increased or decreased by appropriately changing the phases of colliding solitons without altering the walk-off length and the initial energy distribut…