Surface superlattice solitons in nonlocal nonlinear media

We analyse surface solitons at the interface between a one-dimensional photonic superlattice and a uniform medium with weak nonlocal nonlinearity. We demonstrate that in deep lattices there exist three kinds of surface solitons when the propagation constant exceeds a critical value, including two on-site solitons and one off-site soliton. These three kinds of surface solitons have unique dynamical properties. If the relative depth of the superlattice is low, there is only one kind of off-site soliton; however, the solitons of this kind can propagate stably, unlike their deep superlattice counterparts. Dipole surface solitons are also investigated, and the stable domain is given.     

非局域表面暗孤子及其稳定性分析

非局域体介质中的暗孤子及表面亮孤子由于在光通信领域的潜在应用而受到极大关注,然而到目前为止却没有对非局域表面暗孤子的研究.在线性介质和非局域非线性介质的分界面上,数值模拟得到了1+1维非局域基态和二阶表面暗孤子,研究了它们的波形与传播常数和介质非局域程度的关系,基于它们的稳定性分析进行了理论推导和数值模拟.稳定性分析结果表明:1+1维非局域基态表面暗孤子在其存在区域总是稳定的,而二阶表面暗孤子是区域不稳定的,其不稳定区域的宽度与传播常数以及介质的非局域程度有关系,且受传播常数的影响更大.加噪声的初始输入传输图验证了稳定性分析结果的正确性.     

Two-color surface lattice solitons

We study the properties of surface solitons generated at the edge of a semi-infinite photonic lattice in nonlinear quadratic media, namely two-color surface lattice solitons. We analyze the impact of phase mismatch on the existence and stability of nonlinear surface modes and find novel classes of two-color twisted surface solitons, which are stable in a large domain of their existence.     

Lattice-supported surface solitons in nonlocal nonlinear media

We reveal that lattice interfaces imprinted in nonlocal nonlinear media support surface solitons that do not exist in other similar settings, including interfaces of local and nonlocal uniform materials. We show the impact of nonlocality on the domains of existence and stability of the surface solitons, focusing on new types of dipole solitons residing partially inside the optical lattice. We find that such solitons feature strongly asymmetric shapes and that they are stable in large parts of their existence domain.     

Nonlocal surface-wave solitons

We demonstrate, experimentally and theoretically, surface-wave solitons occurring at the interface between a dielectric medium (air) and a nonlinear material with a very long-range nonlocal response. These surface solitons are always attracted toward the surface, and unlike their Kerr-like counterparts, they do not exhibit a power threshold.     

Discrete surface solitons in semi-infinite binary waveguide arrays

We analyze discrete surface modes in semi-infinite binary waveguide arrays, which can support simultaneously two types of discrete solitons. We demonstrate that the analysis of linear surface states in such arrays provides important information about the existence of nonlinear surface modes and their properties. We find numerically the families of both discrete surface solitons and nonlinear Tamm (gap) states and study their stability properties.     

Surface defect solitons at interfaces between dual-frequency and simple lattices

We reveal theoretically the existence and stability of surface defect solitons (SDSs) at interfaces between dual-frequency and simple lattices with focusing saturable nonlinearity. Solitons with some unique properties exist in such composite structures with the change of defect intensity. For zero defect or positive defect, the surface solitons exist at the semi-infinite gap and cannot exist in the first gap, and solitons are stable at lower power but unstable at high power. For the case of negative defect, the surface solitons exist not only in the semi-infinite gap, but also in the first gap. With increasing the defect depth, the stable region of surface solitons becomes narrower in the semi-infinite gap, these solitons are stable within a moderate power region in the first gap within unstable solitons in the entire semi-infinite gap.     

Dynamics of surface dipole and tripole solitons in nonlocal nonlinear media with optical lattice field

We find the existence conditions for stationary dipole and tripole surface solitons formed at the interface of a nonlocal nonlinear medium and a lattice with linearly modulated frequency. We investigate how the degree of nonlocality, the depth, and the modulation frequency of the optical lattice field affect on the existence of the surface solitons and their dynamics. The relationship between the power and the model parameters is identified. The stability of the surface dipole and tripole solitons is numerically investigated.     

Surface solitons supported by one-dimensional composite Bessel optical lattices

We address the existence of surface solitons at an interface in a defocusing cubic medium with an imprinted one-dimensional （1D） composite Bessel optical lattice. This setting is composed of two Bessel lattices with different orders and different modulation depths, separated beside both sides of an interface. Stability analysis and numerical propagation simulations prove that solitons supported by the model are dynamically stable in the entire domain of their existence. The order of lattice determines the shape of soliton, and the amplitude of soliton depends on the lattice modulation depth. The experimental realization of the scheme is also proposed. Our results may provide another effective way of controlling the shapes of surface solitons and thus their evolutions by introducing a new freedom degree.     

Soliton Solutions,B/icklund Transformations and Lax Pair for a （3 ＋ 1）-Dimensional Variable-Coefficient Kadomtsev-Petviashvili Equation in Fluids

Under investigation in this paper is a （3 q- 1）-dimensional variable-coefficient Kadomtsev-Petviashvili equation, which describes the propagation of surface and internal water waves. By virtue of the binary Bell polynomials, symbolic computation and auxiliary independent variable, the bilinear forms, soliton solutions, Backlund transformations and Lax pair are obtained. Variable coefficients of the equation can affect the solitonic structure, when they are specially chosen, while curved and linear solitons are illustrated. Elastic collisions between/among two and three solitons are discussed, through which the solitons keep their original shapes invariant except for some phase shifts.     

Frequency characteristics of the dark and bright surface solitons at a nonlinear metamaterial interface

We investigate the generation and properties of dark and bright surface waves at the interface of a conventional medium and a metamaterial. It is shown that the stable dark and bright surface solitons can coexist even when the nonlinear Kerr coefficients of the two media are negative, completely different from those at the interface between two conventional media. Most importantly, both the dark and bright surface solitons exist only within a certain range of the effective refractive index of the metamaterial, greatly depending on the frequency of the electromagnetic wave propagating in it. Therefore, the generation conditions for surface solitons, and the properties of the generated surface solitons such as the peak positions and the intensity of the dark and bright surface solitons, can be controlled by adjusting the structure parameters of the metamaterial and/or the frequency of the electromagnetic wave.     

Steady-State Spatial Solitons in Low-Amplitude Regime in Biased Photorefractive-Photovoltaic Crystals

A theory of the space-charge field is improved in biased photorefractive-phorovoltaic crystals. Steady-state spatial solitons are obtained in the low-amplitude regime in biased photorefractive-photovoltaic crystals. When photovoltaic effect is neglected, these solitons are screening solitons, and their space-charge field is the space-charge field of screening solitons. When the external field is absent, these solitons are photovoltaic solitons for the closed or the open circuit and we also predict that gray solitons exist in photorefractive-photovoltaic crystals, and their space-charge field is the space-charge field of photovoltaic solitons.     

Asymmetrical surface soliton trains

We elucidate the existence, stability and propagation dynamics of multi-spot soliton packets in focusing saturable media. Such solitons are supported by an interface beside which two harmonically photonic lattices with different modulation depths are imprinted. We show that the surface model can support stable higher-order structures in the form of asymmetrical surface soliton trains, which is in sharp contrast to homogeneous media or uniform harmonic lattice modulations where stable asymmetrical multi-peaked solitons do not exist. Surface trains can be viewed as higher-order soliton states bound together by several different lowest order solitons with appropriate relative phases. Their existence as stable objects enriches the concept of compact manipulation of several different solitons as a single entity and offers additional freedom to control the shape of solitons by adjusting the modulation depths beside the interface.     

Two-dimensional stationary nonlinear surface solitons in nonlocal nonlinear media

We address two-dimensional surface solitons occurring at the interface between a semi-infinite linear medium and a semi-infinite nonlocal nonlinear medium. We find that there exist stable single and dipole surface solitons. The properties of the surface solitons can be affected by the degree of nonlocality. Interestingly, only when the degree of nonlocality is greater than a critical value, the surface solitons can exist.     

Surface defect gap solitons in superlattices with self-defocusing nonlinearity

We put forward the existence and stability of defect surface gap solitons at the interface between uniform media and an superlattice with self-defocusing nonlinearity. We reveal that the defect plays the significant role in controlling the region of solitons existing. Various solitons are found to be existed in different gaps for different defects. For positive defects, fundamental solitons can exist stably in the semi-infinite gap, and dipole solitons can exist stably in the first gap but they are unstable in the second gap. For zero or negative defects, fundamental and dipole solitons can exist stably in the first gap and the second gap, respectively.     

Steady-State Spatial Solitons in Low-Amplitude Regime in Biased Photorefractive-Photovoltaic Crystals

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｓｔｅａｄｙ ｓｔａｔｅｐｈｏｔｏｒｅｆｒａｃｔｉｖｅ (ＰＲ)ｓｐａｔｉａｌｓｏｌｉｔｏｎｓ[1～ 3] ｈａｖｅｂｅｅｎｉｎｖｅｓｔｉｇａｔｅｄｅｘｔｅｎｓｉｖｅｌｙｉｎｔｈｅｐａｓｔｆｅｗｙｅａｒｓ.Ａｔｐｒｅｓｅｎｔｔｈｅｓｅａｒｅｔｗｏｄｉｆｆｅｒｅｎｔｋｉｎｄｓｏｆｓｔｅａｄｙ ｓｔａｔｅＰＲｓｏｌｉｔｏｎｓ :ｓｃｒｅｅｎｉｎｇ[1 ,2 ] ｓｏｌｉｔｏｎｓａｎｄｐｈｏｔｏｖｏｌｔａｉｃ (ＰＶ) [3]ｓｏｌｉｔｏｎｓ.Ｍｏｒｅｒｅｃｅｎｔｌｙ ,ｗｅｈａｖｅｓｈｏｗｎｔｈｅｏ…     

Surface lattice solitons in diffusive nonlinear media

We address the properties of surface solitons supported by optical lattices imprinted in photorefractive media with asymmetrical diffusion nonlinearity. Such solitons exist only in finite gaps of the lattice spectrum. In contrast to latticeless geometries, where surface waves exist only when nonlinearity deflects light toward the material surface, the surface lattice solitons exist in settings where diffusion would cause beam bending against the surface.     

Surface superlattice gap solitons

We demonstrate that specific surface superlattice gap solitons can be supported at an interface between a one-dimensional photonic superlattice and a uniform medium with saturable nonlinearity. The solitons are stable in the semi-infinite gap but do not exist in the first gap. With the decrease of the power, the solitons jump from the surface site to the next one, and they may continue the motion into the lattices, which offers potential applications for the routing of optical signals.     

Surface self-induced transparency solitons at an interface of gallium arsenide and a left-handed material

The theory of surface solitons in a system composed of gallium arsenide and a left-handed metamaterial that has semiconductor quantum dots at the interface between the media is constructed. The formation of surface solitons under the conditions of self-induced transparency upon the excitation of exciton and biexciton transitions in quantum dots is considered. Explicit analytical expressions for solitons (2π-pulses) of surface TM modes in experimentally feasible conditions are obtained. It is shown that the parameters of the surface optical soliton depend on the negative magnetic permeability of the left-handed metamaterial.     

加外电场的光伏光折变晶体中的空间孤子波

证明了在加外电场的光伏光折变晶体中存在着明、暗稳态空间孤子波.它源于对外电场的非均匀空间屏蔽和光伏效应.同已报道的稳态光折变空间孤子相比，它具有不同的特性和物理根源.当外电场足够强时，它类似于屏蔽孤子；当外电场为零时，它退化成闭路条件下的光伏孤子. 关键词：