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1.
The transfer matrix method was modified to explore the Kerr nonlinearity influence on laser radiation propagation in a one‐dimensional photonic crystal. The suggested spatial distribution of the refractive index allows to remove minibands and to make the transmission curve much steeper. Plain and steep photonic band gap edges are effective in creation of transmission anisotropy of powerful laser radiation. The investigated photonic crystal has a strong anisotropic optical transmission and acts as an optical analog of the electronic diode. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Ruiyu Hao 《Optics & Laser Technology》2011,43(1):25-28
In this paper, we present the (1+1)-dimensional inhomogeneous nonlinear Schrödinger (NLS) equation that describes the propagation of optical waves in nonlinear optical systems exhibiting optical lattice, inhomogeneous nonlinearity and varying diffraction at the same time. A series of interesting properties of spatial solitons are found from the numerical calculations, such as the stable propagation in the a nonperiodic optical lattice induced by periodic diffraction variations and periodic nonlinearity variations. Finally, the interaction of neighboring spatial solitons in a nonperiodic optical lattice is discussed, and the results reveal that two spatial solitons can propagate periodically and separately in the optical lattice without interaction. 相似文献
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Qiongtao Xie 《Central European Journal of Physics》2014,12(12):830-835
We present exact analytical results for bright and dark solitons in a type of one-dimensional spatially inhomogeneous nonlinearity. We show that the competition between a homogeneous self-defocusing (SDF) nonlinearity and a localized self-focusing (SF) nonlinearity supports stable fundamental bright solitons. For a specific choice of the nonlinear parameters, exact analytical solutions for fundamental bright solitons have been obtained. By applying both variational approximation and Vakhitov-Kolokolov stability criterion, it is found that exact fundamental bright solitons are stable. Our analytical results are also confirmed numerically. Additionally, we show that a homogeneous SF nonlinearity modulated by a localized SF nonlinearity allows the existence of exact dark solitons, for certain special cases of nonlinear parameters. By making use of linear stability analysis and direct numerical simulation, it is found that these exact dark solitons are linearly unstable. 相似文献
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Shear waves with finite amplitude in a one-dimensional resonator in the form of a layer of a rubber-like medium with a rigid
plate of finite mass at the upper surface of the layer are investigated. The lower boundary of the layer oscillates according
to a harmonic law with a preset acceleration. The equation of motion for particles in a resonator is determined using a model
of a medium with a single relaxation time and cubical dependence of the shear modulus on deformation. The amplitude and form
of shear waves in a resonator are calculated numerically by the finite difference method at shifted grids. Resonance curves
are obtained at different acceleration amplitudes at the lower boundary of a layer. It is demonstrated that, as the oscillation
amplitude in the resonator grows, the value of the resonance frequency increases and the shape of the resonance curve becomes
asymmetrical. At sufficiently large amplitudes, a bistability region is observed. Measurements were conducted with a resonator,
where a layer with the thickness of 15 mm was manufactured of a rubber-like polymer called plastisol. The shear modulus of
the polymer at small deformations and the nonlinearity coefficient were determined according to the experimental dependence
of mechanical stress on shear deformation. Oscillation amplitudes in the resonator attained values when the maximum shear
deformations in the layer were 0.4–0.6, which provided an opportunity to observe nonlinear effects. Measured dependences of
the resonance frequency on the oscillation amplitude corresponded to the calculated ones that were obtained at a smaller value
of the nonlinear coefficient. 相似文献
5.
We predict that a photonic crystal fiber whose strands are filled with a defocusing nonlinear medium can support stable bright solitons and also vortex solitons if the strength of the defocusing nonlinearity grows toward the periphery of the fiber. The domains of soliton existence depend on the transverse growth rate of the filling nonlinearity and nonlinearity of the core. Remarkably, solitons exist even when the core material is linear. 相似文献
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Unlike linear nondispersive media, which allow propagation of wave packets of arbitrary forms, nonlinear media admit only certain profiles of traveling waves. Here we examine media with Duffing oscillators, i.e., with bound electrons for which an equilibrium disturbance causes forces proportional to the first and third powers of deviation. We show that the linearly polarized traveling plane waves such media can transmit have profiles modulated as Jacobi elliptic functions. When discussing propagation across an interface between different media, only incidence from the side of the linear medium is considered. Even in this case, to launch a traveling wave in the nonlinear medium, a severe restriction must be imposed on the incident wave’s amplitude. 相似文献
10.
A. A. Kalinovich I. G. Zakharova V. A. Trofimov 《Bulletin of the Russian Academy of Sciences: Physics》2018,82(1):13-16
A way of forming a new class of solitons—chirped (or aberrational) solitons—when a pulse passes through a layered nonlinear structure in a cubically nonlinear medium is demonstrated by means of computer simulation. It is shown that the pulse frequency modulation of the resulting solitons is nonlinear. 相似文献
11.
In this paper the influence of spatial matter inhomogeneities on laser action is investigated theoretically. The calculations are based on nonlinear laser theory for the amplitudes of the empty-cavity modes. The nonlinear mode interactions like mode suppression or phase locking are modified by spatial inhomogeneities. There also arises a linear coupling among the cavity modes in general leading to monochromatically oscillating states which are superpositions of the empty-cavity eigenfunctions. 相似文献
12.
G. G. Ivanov 《Russian Physics Journal》1980,23(12):999-1002
For a self-gravitating massless conformally invariant scalar field a solution is obtained to the Einstein equations for which the geometry of space-time remains arbitrary. For a scalar field with cubic nonlinearity, a static solution to the Einstein equations possessing plane symmetry is found. A cosmological model with nonlinear scalar field in the class of conformally flat Friedmann metrics is investigated. An example is given of an exact solution to the equations of the gravitational field with singularity in the infinite past.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 18–22, December, 1980. 相似文献
13.
B. B. Sevruk 《Journal of Applied Spectroscopy》2006,73(5):701-706
A semi-discrete dynamic model has been developed for the formation of the spatial structure of wave fields in a medium with
cubic nonlinearity. The characteristic features of self-focusing and conical modulation of intense Bessel-Gaussian light beams
of different orders have been studied in different stages of their evolution during propagation. It has been shown that as
a result of nonlinear refraction, in the far zone wave structures are formed consisting of three spatially separated conical
beams. Increasing the cone angle of the wave vectors leads to a decrease in the effect of conical modulation of the radiation,
and improves the structural stability of the beam. The considered self-modulation effects can be used for passive limiting
of the laser radiation power.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 626–630, September–October, 2006. 相似文献
14.
An optical medium whose nonlinearity can be spatially adjusted is considered to study beam reshaping. The concept is applied to perform adiabatic self-focusing of broad beams. Experimental results are obtained in a photorefractive lithium niobate crystal where the self-focusing nonlinearity is controlled over propagation by a temperature gradient. As a demonstration, gradual self-focusing is shown to transform an incoming beam into an output circular spot 10 times smaller over a 2 cm long crystal submitted to a 30 °C temperature gradient. Once formed, the adiabatic self-focused beam has inscribed a funnel waveguide in the crystal. 相似文献
15.
The theory of the isothermal Hall-effect in intrinsic material is corrected taking into account arbitrary surface and bulk recombination and the departure from local electrical neutrality. The resulting formulas for the Hall voltage, the Hall field, the charge density, and the electron-hole current are valid for a weak magnetic field. 相似文献
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《中国光学快报(英文版)》2020,(6)
An aberration-free imaging technique was used to design a double-spherically bent crystal spectrometer with high energy and spatial resolutions to ensure that the individual spectral lines are represented as perfectly straight lines on the detector. After obtaining the matched parameters of the two crystals via geometry-based optimization, an alignment method was employed to allow the spacing between the crystals and the detector to be coupled with the source. The working principle of this spectrum-measuring scheme was evaluated using a Cu X-ray tube. High-quality spectra with energy resolutions(E/ΔE) of approximately 3577 were obtained for a relatively large source size. 相似文献
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