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- 摘要
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- 实验方案
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Generation of solitons in media with arbitrary degree of nonlocality using an optimization procedure
摘要： Using a recently developed technique based on the Rayleigh-Ritz optimization principle, we generate solitons for media with an arbitrary degree of nonlocality. We demonstrate that it is possible to obtain a plethora of complex self-trapped beams using known solutions to the harmonic oscillator for one-dimensional (1D), 2D, and 3D systems, but working directly with a generalized nonlinear nonlocal Schr?dinger equation. We compare the parameters obtained variationally between the phenomenological Gaussian response and other more realistic nonlocal responses. We report that, for both kinds of nonlocal models, our approach obtains variational solutions that can remain self-trapped for certain conditions. We corroborate that, in general, the soliton dynamics can be different between the Gaussian response and the more realistic media for an arbitrary degree of nonlocality.
关键词： nonlinear Schr?dinger equation,variational approximation,nonlocality,solitons,optical beams
更新于2025-09-23 15:22:29
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Dark–bright solitons in spinor polariton condensates under nonresonant pumping
摘要： By adopting a mean-field Gross-Pitaevskii description of spinor polariton Bose-Einstein condensates under nonresonant pumping, we investigate the static and dynamical properties of dark-bright (DB) solitons. We derive the equation of motion for the center of mass of the DB solitons' center analytically by using the Hamiltonian approach. The resulting equation captures how the combination of the open-dissipative character and the spin degrees of freedom of a polariton Bose-Einstein condensate affects the properties of DB solitons, i.e. DB solitons relax by blending with the background at a finite time. In this case, we also determine the lifetime of the DB solitons. Further numerical solutions of the modified dissipative two-component Gross-Pitaevskii equations are in excellent agreement with the analytical results. In the presence of the Langevin noise, we demonstrate that the DB solitons can still propagate for a long time, which is sufficient for their experimental observations within current facilities.
关键词： polariton Bose-Einstein condensate,dark-bright solitons,mean-field method,stochastic GP equations
更新于2025-09-23 15:22:29
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Interactions between M-typed solitons based on nonlinear optimization in dispersion management systems
摘要： Investigations on soliton interactions in dispersion management systems are beneficial to improving the communication capacity. In this paper, the variable-coefficient fifth-order nonlinear Schr?dinger equation, which can be used to describe the soliton interactions in dispersion management systems, is studied analytically. M-typed soliton interactions are presented based on the obtained soliton solutions. Influences of nonlinear effects on M-typed soliton interactions are analyzed. Results indicate that we can effectively control soliton interactions by means of nonlinear optimization of dispersion management systems.
关键词： Soliton interactions,Solitons,Dispersion management systems
更新于2025-09-23 15:22:29
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Pulse delay and group velocity dispersion measurement in V-type electromagnetically induced transparency of hot <sup>85</sup>Rb atom
摘要： Pulse delay with the group velocity dispersion (GVD) characteristics was studied in the V-system configuration. The phase coherency between the pump and the probe laser beams was maintained. We studied the pulse delay and the GVD characteristics with the variation of the type electromagnetically induced transparency in the hyperfine levels of 85Rb atoms with a closed electromagnetically induced transparency of hot 85Rb atom. For a better understanding of the experimental results, we have derived an analytical solution for the three level V-type system. The theoretical plots of the delay and the group velocity dispersion show the same characteristics as we observed in the experiment. This analytical approach can be further generalized for the higher level schemes to calculate different quantities such as susceptibility, group velocity delay or group velocity dispersion characteristics.
关键词： electromagnetically induced transparency,Coherent optical effects,Pulse propagation and temporal solitons
更新于2025-09-23 15:21:21
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Thin Films
摘要： We demonstrate how to extract the material-dependent spin-torque efficiency (ξ) and asymmetry (λ) from the field-current nucleation boundaries of magnetic droplet solitons in orthogonal nano-contact spin-torque oscillators with Cox(Ni80Fe20)1?x, (x = 0 ? 1), fixed layers. As the perpendicular component of the fixed-layer magnetization plays a central role in governing droplet nucleation, the nucleation boundaries exhibit monotonic shifts towards higher perpendicular magnetic fields when the fixed-layer magnetization μ0Ms,p is tuned from 1.04 to 1.7 T. We then extract ξ and λ from fits to the nucleation boundaries and find that while ξ does not vary with composition, λ increases from 1.5 to 3 with increasing Co content. The analysis of droplet nucleation boundaries is hence a useful tool for the systematic study of both ξ and λ as functions of material composition.
关键词： Cox(Ni80Fe20)1?x,magnetic droplet solitons,spin-torque asymmetry,spin-torque efficiency,nano-contact spin-torque oscillators
更新于2025-09-23 15:21:21
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Charged solitons in branched conducting polymers
摘要： We consider the dynamics of charged solitons in branched conducting polymers, such as, e.g., trans-polyacetylene. An effective model based on the sine-Gordon equation on metric graphs is used for computing the charge transport and scattering of charge carriers at the polymer branching points. The condition for the ballistic charge carrier transport is revealed.
关键词： metric graphs,charged solitons,charge transport,branched conducting polymers,ballistic transport,sine-Gordon equation
更新于2025-09-23 15:21:21
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Optical bright and dark soliton solutions for coupled nonlinear Schr??dinger (CNLS) equations by the variational iteration method
摘要： This paper studies optical bright and dark soliton solutions for coupled nonlinear Schr¨odinger (CNLS) equations in the anomalous and dispersive regimes. We operate the variational iteration method (VIM) to derive a set of diverse types of bright and dark optical soliton solutions. The VIM gives the solution in a rapidly convergent series without any need for physical restrictions or changing the nonlinearity issue. The presented analysis shows the pertinent features of the VIM method in handling nonlinear evolution equations.
关键词： optical solitons,variational iteration method.,Coupled nonlinear Schr¨odinger equation
更新于2025-09-23 15:21:01
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Self-frequency shift effect for chirped self-similar solitons in a tapered graded-indexed waveguide
摘要： This work studies the transmission dynamics of self-similar optical beams through an inhomogeneous tapered graded-index waveguide under diffraction and nonlinearity management as well as self-frequency shift arising from stimulated Raman scattering (SRS). A similarity transformation connecting with the constant-coefficient higher-order nonlinear Schr? dinger’s equation (HNLSE) is employed to construct new self-similar solitons for wave field. We demonstrate that the self-frequency shift term alone turns the self-similar pulses to be nonlinear chirped. The results indicate that the nonlinear chirp related to the self-similar localized waves is directly proportional to the intensity of the optical beam. The necessary and sufficient conditions on tapered graded-index nonlinear waveguide parameters for such nonlinearly chirped self-similar localized waves exist in this model are suggested. The dynamical behaviors of those chirped optical similaritons are also investigated in a periodically distributed waveguide as well as a diffraction decreasing waveguide.
关键词： Chirp,Solitons,Similaritons
更新于2025-09-23 15:21:01
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Perturbed nonlinear Schr??dinger dynamical wave equation with Kerr media in nonlinear optics via optical solitons
摘要： In this paper, we have presented the analytical analysis of integrable perturbed nonlinear Schr¨odinger (PNLSE) equation with third-order dispersion (TOD) in Kerr media using our newly proposed technique, extended modi?ed auxiliary equation mapping method. By the implementation of this technique, we have obtained a variety of some new families and more general form of exact traveling wave solutions including triangular-type solutions, periodic and doubly periodic-like solutions, combined soliton-like solutions, kink and anti-kink type soliton-like solutions using three parameters which is the key di?erence of our newly proposed method. PNLSE is a well-known governing model to study the propagation of optical solitons in nonlinear optical ?bers and other telecommunication networks with a type of Kerr law nonlinearity. This particular type of nonlinearity originates when a light wave in an optical ?ber is subjected to nonlinear responses. For graphical representation of our newly found results, we have presented them with detailed dynamical physical representation using Mathematica 10.4 to explain in a more e?cient manner the behavior of di?erent physical structures of solutions. Also, the computational work and e?ciency of the method demonstrate the reliability, straightforwardness, and simplicity of the technique for solving other nonlinear complicated partial di?erential equations.
关键词： mathematical methods,Mathematical physics,perturbed NLSE,optical solitons
更新于2025-09-23 15:21:01
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2a??10???μm Mida??Infrared Fibera??Based Supercontinuum Laser Source: Experiment and Simulation
摘要： Mid-infrared supercontinuum (mid-IR SC) sources in the 2–20 μm molecular fingerprint region are in high demand for a wide range of applications including optical coherence tomography, remote sensing, molecular spectroscopy, and hyperspectral imaging. Herein, mid-IR SC generation is investigated in a cascaded silica-ZBLAN-chalcogenide fiber system directly pumped with a commercially available pulsed fiber laser operating in the telecommunications window at 1.55 μm. This fiber-based system is shown to generate a flat broadband mid-IR SC covering the entire range from 2 to 10 μm with several tens of mW of output power. This technique paves the way for low cost, practical, and robust broadband SC sources in the mid-IR without the requirement of mid-infrared pump sources or Thulium-doped fiber amplifiers. A fully realistic numerical model used to simulate the nonlinear pulse propagation through the cascaded fiber system is also described and the numerical results are used to discuss the physical processes underlying the spectral broadening in the cascaded system. Finally, recommendations are provided for optimizing the current cascaded system based on the simulation results.
关键词： soft-glass fibers,nonlinear optics and solitons,supercontinuum generation,chalcogenide fibers,fiber lasers,ZBLAN fibers
更新于2025-09-23 15:21:01