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We put forward the concept of resonant, Rabi-like oscillatons and adiabatic transitions between confined light modes in properly modulated multimode waveguides. The phenomenon is shown to take place in both the linear and the nonlinear regimes. In addition, we find that the mode transitions occur not only in simple geometries, but also in complex confining multimode structures. The phenomenon is analogous to the familiar stimulated state transitions that occur in multilevel quantum systems. 相似文献
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The possibility of formation of a basic (stationary) and an additional (moving) high-absorption domain in an optically bistable system, based on high absorption, is demonstrated. A semiconductor with the absorption coefficient dependent on the concentration of free charge carriers in the conduction band is considered as a nonlinear medium. Under certain conditions, an optical beam passing through the stationary high-absorption domain acquires an annular profile and, after traveling a certain distance, transforms into a Gaussian beam with an intensity on the axis sufficient to switch the medium-beam system to the upper state. This moving domain periodically disappears and reappears due to diffusion processes. 相似文献
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We address the phenomenon of soliton self-bending in Kerr-type nonlocal nonlinear media with an imprinted transverse periodic modulation of the linear refractive index. We show that the imprinted optical lattice makes possible to control the mobility of soliton by varying the depth and the frequency of the linear refractive index modulation. 相似文献
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We show that the geometrically induced potential existing in undulated slab waveguides dramatically affects the properties of solitons. In particular, whereas solitons residing in the potential maxima do not feature power thresholds and are stable, their counterparts residing in the potential minima are unstable and may exhibit a power threshold for their existence. Additionally, the geometric potential is shown to support stable multipole solitons that cannot be supported by straight waveguides. Finally, the geometric potential results in the appearance of the effective barriers that prevent transverse soliton motion. 相似文献
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We address the properties of multivortex soliton complexes supported by multiring gain landscapes in focusing Kerr nonlinear media with strong two-photon absorption. Stable complexes incorporating two, three, or four vortices featuring opposite or identical topological charges are shown to exist. In the simplest geometries with two amplifying rings vortex twins with equal topological charges exhibit asymmetric intensity distributions, while vortex anti-twins may be symmetric or asymmetric, depending on the gain level and separation between rings. 相似文献
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We discover that a spatially localized gain supports stable vortex solitons in media with cubic nonlinearity and two-photon absorption. The interplay between nonlinear losses and gain in amplifying rings results in the suppression of otherwise ubiquitous azimuthal modulation instabilities of radially symmetric vortex solitons. We find that the topology of the gain profile imposes restrictions on the maximal possible charge of vortex solitons. Symmetry breaking occurs at high gain levels, resulting in the formation of necklace vortex solitons composed of asymmetric bright spots. 相似文献
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V. A. Vysloukh V. Kutuzov V. M. Petnikova V. V. Shuvalov 《Journal of Experimental and Theoretical Physics》1997,84(2):388-394
An analytical model, which describes the drift and diffusion mechanisms for the formation of the nonlinear response (local
and nonlocal nonlinearities) of photorefractive crystals on the microscopic level, is constructed. New types of stable self-consistent
distributions of the light field intensity, i.e., spatial solitons, are found. The trajectories of their motion (self-bending)
are calculated, and the possibility of observing a new nonlinear-optical effect in photorefractive crystals, viz., the formation
of spatial shock waves, is demonstrated. The modulation instability appearing when plane waves propagate in photorefractive
crystals is analyzed, and the characteristic spatial scales of the light field distribution formed as a result of self-interaction
(fanning) are determined. The results of the analysis are confirmed by computer simulation data.
Zh. éksp. Teor. Fiz. 111, 705–716 (February 1997) 相似文献
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