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We demonstrate that a weak defocusing Kerr effect in an optical medium with predominantly quadratic [or chi((2))] nonlinear response can eliminate the parametric modulational instability of plane waves, leading to the existence of stable two-wave dark and vortex spatial solitons. 相似文献
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通过数值模拟的方法对非局域非线性自散焦材料中的光学 涡旋孤子的传输特性以及相互作用特性进行了研究. 研究表明, 拓扑荷|m|=1的非局域涡旋孤子是稳定的, 而拓扑荷|m|>1的非局域涡旋孤子均具有拓扑不稳定性. 在微扰存在的情况下以及在近距离相互作用的过程中, |m|>1的涡旋孤子会分裂成一系列的|m|=1的涡旋孤子. 非局域涡旋孤子与局域涡旋孤子具有相同的长距离相互作用模式, 即点涡旋相互作用模式. 但两者的短距离相互作用存在一些差别, 在相同的距离下, 两涡旋间的相互绕转的周期随着材料的非局域响应长度增大而增大.
关键词:
非局域非线性薛定谔方程
自散焦
涡旋孤子 相似文献
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The combined effects of diffraction and Poynting vector walk-off in second-harmonic generation with pump beams that contain screw phase dislocations is addressed for what is believed to be the first time. We predict the spontaneous nucleation of multiple vortex twins whose subsequent explosion can yield quasi-aligned patterns of single-charge vortices. 相似文献
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The complex dynamics of intracavity three-wave mixing are discussed. Detailed results obtained by numerical simulation of routes to chaos are presented for a wide range of parameters. As the pump intensity increases, a complex sequence of alternating regular and chaotic self-modulation regimes is observed. The relationship between these regimes and soliton formation and propagation is analyzed. 相似文献
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We study higher-order nonlinear modes in the form of vortex solitons and soliton clusters propagating in the waveguides created
in photonic crystal fibers made of a material with the focusing Kerr nonlinearity. We find numerically different families
of such nonlinear modes with a nontrivial topology and study their bifurcations. We also study the soliton stability to propagation.
We demonstrate that waveguides in photonic crystal fibers may support a variety of soliton clusters with the symmetries that
may differ from the lattice symmetry. We also discuss briefly the case of a dual-core coupler created by two neighboring cores
in a photonic crystal fiber and find numerically the profiles of symmetric and asymmetric nonlinear modes. 相似文献
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The interaction of a spin wave with a stationary Bloch point is studied. The topological non-trivial structure of the Bloch point manifests in the propagation of spin waves endowing them with a gauge potential that resembles the one associated with the interaction of a magnetic monopole and an electron. By pursuing this analogy, we are led to the conclusion that the scattering of spin waves and Bloch points is accompanied by the creation of a magnon vortex. Interference between such a vortex and a plane wave leads to dislocations in the interference pattern that can be measurable by means of magnon holography. 相似文献
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We show theoretically that the waves generated through the generic parametric three- or four-wave-mixing processes exhibit, as a general rule, a hidden coherence characterized by skewed coherence lines along specific space-time trajectories. Our study generalizes the concept of coherence in the sense that these previously unrecognized coherent states cannot be described through the standard definitions of spatial and temporal coherence. 相似文献
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We demonstrate, for the first time to our knowledge, optical parametric oscillation based on four-wave mixing in microstructure fiber. The measured wavelength-tunability range of the device (40 nm) and the threshold-pump peak power (34.4 W) are in good agreement with the theory of four-wave mixing in optical fibers. The ellipticity of the fiber's polarization modes allows the device to be implemented in a relatively simple Fabry-Perot configuration. Spectral peaks that are due to cascaded-mixing processes are easily observed in our setup, which may provide a way to extend the tunability range of existing high-power lasers. 相似文献
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D. A. Akimov M. V. Alfimov A. A. Ivanov A. B. Fedotov T. A. Birks W. J. Wadsworth P. St. J. Russell S. O. Konorov O. A. Kolevatova A. A. Podshivalov A. M. Zheltikov 《JETP Letters》2003,77(1):7-11
Doubly phase-matched cascaded parametric wave mixing of femtosecond laser pulses in tapered fibers is experimentally demonstrated. Fibers with an appropriately tailored dispersion profile allow simultaneous phase matching for two types of nonlinear-optical processes-third-harmonic generation and parametric four-wave mixing. Doubly phase-matched cascaded parametric interactions of ultrashort light pulses give rise to a manifold of new spectral components, expanding substantially the capabilities of the available laser sources of ultrashort pulses. 相似文献
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We demonstrate that families of vortex solitons are possible in a bidispersive three-dimensional nonlinear Schr?dinger equation. These solutions can be considered as extensions of two-dimensional dark vortex solitons which, along the third dimension, remain localized due to the interplay between dispersion and nonlinearity. Such vortex solitons can be observed in optical media with normal dispersion, normal diffraction, and defocusing nonlinearity. 相似文献
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Neshev DN Dreischuh A Shvedov V Desyatnikov AS Krolikowski W Kivshar YS 《Optics letters》2008,33(16):1851-1853
We demonstrate experimentally the formation of polychromatic single- and double-charge optical vortex solitons by employing a lithium niobate crystal as a nonlinear medium with defocusing nonlinearity. We study the wavelength dependence of the vortex core localization and observe self-trapping of polychromatic vortices with a bandwidth spanning over more than 70 nm for single-charge and 180 nm for double-charge vortex solitons. 相似文献
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We study self-localized second-band vortex states in two-dimensional photonic lattices and find stable ring solitons whose phase forms an array of counterrotating vortices. We also identify composite solitons in which a second-band vortex is jointly trapped with a mode arising from the first band and study their stability. When such a composite entity is unstable, it disintegrates while exchanging angular momentum between its constituents, eventually stabilizing into another form of composite soliton. 相似文献
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We investigate the formation of high-order polarization vortex spatial solitons. The high-order polarization vortex solitons have novel polarization states which are different from fundamental polarization vortex solitons and have rotational symmetry only in intensity. It is proved that the polarization vortex solitons cannot carry vortex phase. The existence domain and dynamical characteristic of these high-order polarization vortex solitons in Bessel optical lattices are discussed in detail. 相似文献
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We reveal the existence of asymmetric vortex solitons in ideally symmetric periodic lattices and show how such nonlinear localized structures describing elementary circular flows can be analyzed systematically using the energy-balance relations. We present the examples of rhomboid, rectangular, and triangular vortex solitons on a square lattice and also describe novel coherent states where the populations of clockwise and anticlockwise vortex modes change periodically due to a nonlinearity-induced momentum exchange through the lattice. Asymmetric vortex solitons are expected to exist in different nonlinear lattice systems, including optically induced photonic lattices, nonlinear photonic crystals, and Bose-Einstein condensates in optical lattices. 相似文献
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Optical and Quantum Electronics - It is almost common knowledge now that particles also possess properties of waves. But, can localized wave-packets behave and interact like particles? This article... 相似文献