This paper predicts that grey spatial solitons can exist in two-photon photorefractive materials. In steady state and undcr appropriate external bias conditions, it obtains the grey spatial soliton solutions of the op...This paper predicts that grey spatial solitons can exist in two-photon photorefractive materials. In steady state and undcr appropriate external bias conditions, it obtains the grey spatial soliton solutions of the optical wave evolution equation. The intensity profile, phase distribution, and transverse velocity of these grey solitons are discussed.展开更多
The fundamental and second order strongly nonlocal solitons of the nonlocal nonlinear Schrodinger equation for several types of nonlocal responses are calculated by Ritz's variational method. For a specific type of n...The fundamental and second order strongly nonlocal solitons of the nonlocal nonlinear Schrodinger equation for several types of nonlocal responses are calculated by Ritz's variational method. For a specific type of nonlocal response, the solutions of the strongly nonlocal solitons with the same beam width but different degrees of nonlocality are identical except for an amplitude factor. For a nonlocal case where the nonlocal response function decays in direct proportion to the mth power of the distance near the source point, the power and the phase constant of the strongly nonlocal soliton are in inverse proportion to the (m + 2)th power of its beam width.展开更多
This paper studies numerically the dark incoherent spatial solitons propagating in logarithmically saturable nonlinear media by using a coherent density approach and a split-step Fourier approach for the first time. U...This paper studies numerically the dark incoherent spatial solitons propagating in logarithmically saturable nonlinear media by using a coherent density approach and a split-step Fourier approach for the first time. Under odd and even initial conditions, a soliton triplet and a doublet are obtained respectively for given parameters. Simultaneously, coherence properties associated with the soliton triplet and doublet are discussed. In addition, if the values of the parameters are properly chosen, five and four splittings from the input dark incoherent spatial solitons can also form. Lastly, the grayness of the soliton triplet and that of the doublet are studied, in detail.展开更多
The dynamical evolution and stability of bright dissipative holographic solitons in biased photorefractive materials in which the self-trapping beam obtains a gain from the pump beam via two-wave mixing has been inves...The dynamical evolution and stability of bright dissipative holographic solitons in biased photorefractive materials in which the self-trapping beam obtains a gain from the pump beam via two-wave mixing has been investigated numerically. Results show that these solitons are stable relative to small perturbations. Adjusting some system parameters, such as the bias field and the angle between beams, can easily control the generation of such solitons. Potential applications in optical switches or repeaters are discussed.展开更多
We study the propagation of (l+l)-dimensional spatial soliton in a nonlocal Kerr-type medium with weak non- locality. First, we show that an equation for describing the soliton propagation in weak nonlocality is a ...We study the propagation of (l+l)-dimensional spatial soliton in a nonlocal Kerr-type medium with weak non- locality. First, we show that an equation for describing the soliton propagation in weak nonlocality is a nonlinear Schr6dinger equation with perturbation terms. Then, an approximate analytical solution of the equation is found by the perturbation method. We also find some interesting properties of the intensity profiles of the soliton.展开更多
The purpose of this paper is to present an all-optical EXOR for cryptographic application based on spatial soliton beams. The device is based on the propagation and interactions properties of spatial soliton in a Kerr...The purpose of this paper is to present an all-optical EXOR for cryptographic application based on spatial soliton beams. The device is based on the propagation and interactions properties of spatial soliton in a Kerr nonlinear material. The interaction force between parallel soliton beam is analyzed from the analytical point of view and an exact solution is presented.展开更多
We study analytically and numerically the propagation of spatial solitons in a two-dimensional stronglynonlocal nonlinear medium. Exact analytical solutions in the form of self-similar spatial solitons are obtained in...We study analytically and numerically the propagation of spatial solitons in a two-dimensional stronglynonlocal nonlinear medium. Exact analytical solutions in the form of self-similar spatial solitons are obtained involvinghigher-order Hermite-Gaussian functions. Our theoretical predictions provide new insights into the low-energy spatialsoliton transmission with high fidelity.展开更多
Collisions of spatial solitons occurring in the nonlinear Schringer equation with harmonic potential arestudied,using conservation laws and the split-step Fourier method.We find an analytical solution for the separati...Collisions of spatial solitons occurring in the nonlinear Schringer equation with harmonic potential arestudied,using conservation laws and the split-step Fourier method.We find an analytical solution for the separationdistance between the spatial solitons in an inhomogeneous nonlinear medium when the light beam is self-trapped inthe transverse dimension.In the self-focusing nonlinear media the spatial solitons can be transmitted stably,and theinteraction between spatial solitons is enhanced due to the linear focusing effect (and also diminished for the lineardefocusing effect).In the seff-defocusing nonlinear media,in the absence of seff-trapping or in the presence of linearself-defocusing,no transmission of stable spatial solitons is possible.However,in such media the linear focusing effectcan be exactly compensated,and the spatial solitons can propagate through.展开更多
We investigate theoretically the temperature effects on the evolution and stability of a separate screening brightdark soliton pair formed in a serial non-photovoltaic photorefractive crystal circuit. Our numerical re...We investigate theoretically the temperature effects on the evolution and stability of a separate screening brightdark soliton pair formed in a serial non-photovoltaic photorefractive crystal circuit. Our numerical results show that, for a stable bright-dark soliton pair originally formed in a crystal circuit at given temperatures, when one crystal temperature changes, the soliton supported by the other crystal will evolve into another stable soliton if the temperature change is quite small, whereas it will become unstable and experience larger cycles of compression or break up into beam filaments if the temperature difference is big enough. The dark soliton is more sensitive to the temperature change than the bright one.展开更多
We investigate theoretically waveguides induced by screening-photovoltaic solitons in biased photorefractive-photovoltaic crystals. We show that the number of guided modes in a waveguide induced by a bright screening ...We investigate theoretically waveguides induced by screening-photovoltaic solitons in biased photorefractive-photovoltaic crystals. We show that the number of guided modes in a waveguide induced by a bright screening photovoltaic soliton increases monotonically with the increasing intensity ratio of the soliton, which is the ratio between the peak intensity of the soliton and the dark irradiance. On the other hand, waveguides induced by dark screening-photovoltaic solitons are always single mode for all intensity ratios and the confined energy near the centre of a dark screening-photovoltaic soliton increases monotonically with the increasing intensity ratio. When the bulk photovoltaic effect is neglectable, these waveguides are those induced by screening solitons. When the external field is absent, these waveguides predict those induced by photovoltaic solitons.展开更多
The dynamics evolution of dark holographic solutions in a dissipative system is investigated numerically provided that the double balance, i.e. diffraction is balanced by nonlinearity and loss is balanced by gain, is ...The dynamics evolution of dark holographic solutions in a dissipative system is investigated numerically provided that the double balance, i.e. diffraction is balanced by nonlinearity and loss is balanced by gain, is satisfied. The influence of the system parameters, such as the linear loss of the crystal, the external biased field and the angel between input beams, on the stable propagation of soliton beams is discussed numerically. Results show that such solitons can be easily amplified or absorbed by adjusting these system parameters. Furthermore, numerical simulations indicate that dissipative dark holographic solitons are stable for small perturbation on amplitude.展开更多
The dynamical evolution of both signal and pump beams are traced by numerically solving the coupled-wave equation for a photorefractive two-wave mixing system. The direct simulations show that, when the intensity rati...The dynamical evolution of both signal and pump beams are traced by numerically solving the coupled-wave equation for a photorefractive two-wave mixing system. The direct simulations show that, when the intensity ratio of the pump beam to the signal beam is large enough, the pump beam presents a common decaying behaviour without modulational instability (MI), while the signal beam can evolve into a quasistable spatial soliton within a regime in which the pump beam is depleted slightly. The larger the ratio is, the longer the regime is. Such quasistable solitons can overcome the initial perturbations and numerical noises in the course of propagation, perform several cycles of slow oscillation in intensity and width, and persist over tens of diffraction lengths. From physical viewpoints, these solitons actually exist as completely rigorous physical objects. If the ratio is quite small, the pump beam is apt to show MI, during which the signal beam experiences strong expansion and shrinking in width and a drastic oscillation in intensity, or completely breaks up. The simulations using actual experimental parameters demonstrate that the observation of an effectively stable soliton is quite possible in the proposed system.展开更多
By using semiclassical theory combined with multiple-scale method, we analytically study the linear absorption and the nonlinear dynamical properties in a lifetime broadened Λ-type three-level self-assembled quantum ...By using semiclassical theory combined with multiple-scale method, we analytically study the linear absorption and the nonlinear dynamical properties in a lifetime broadened Λ-type three-level self-assembled quantum dots. It is found that this system can exhibit the transparency, and the width of the transparency window becomes wider with the increase of control light field. Interestingly, a weak probe light beam can form spatial weak-light dark solitons. When it propagates along the axial direction, the soliton will transform into a steady spatial weak-light ring dark soltion. In addition, the stability of two-dimensional spatial optical solitons is testified numerically.展开更多
A theory is presented to investigate the existence and propagation stability of gap solitons in a parity-time (PT) com- plex superlattice with dual periods. In this superlattice, the real and imaginary parts are bot...A theory is presented to investigate the existence and propagation stability of gap solitons in a parity-time (PT) com- plex superlattice with dual periods. In this superlattice, the real and imaginary parts are both in the form of superlattices with dual periods. In the self-focusing nonlinearity, PT solitons can exist in the semi-infinite gap. However, only those gap solitons with low powers can propagate stably, whereas the high-power solitons present periodic oscillation and simultane- ously suffer energy decay. In the self-defocusing nonlinearity, PT solitons only exist in the first gap and all these solitons are stable.展开更多
The existence of one-dimensional bright Kerr solitons is investigated in Kerr media beyond the paraxial approximation. It is found that a nonparaxial soliton with no less than a minimum dimensionless width of about 0....The existence of one-dimensional bright Kerr solitons is investigated in Kerr media beyond the paraxial approximation. It is found that a nonparaxial soliton with no less than a minimum dimensionless width of about 0.76 can exist, which corresponds to the real width about a wavelength. Besides, the coherent interactions between two nonparaxial bright solitons in Kerr media are also investigated in detail. It is found that their separation and intensity ratio have great influence on the coherent interaction between these two solitons. Furthermore, the effect of the relative phase difference on the nonparaxial interaction is quite different from that on the paraxial interaction. Periodical breath, merging, repulsion, and energy transferring can be realized separately by choosing an appropriate initial relative phase between the coherent solitons.展开更多
The incoherent interaction between solitons with different transverse dimensions in a noncentrosymmetric photorefractive crystal is studied both in theory and in experiment. An anomalous incoherent interaction between...The incoherent interaction between solitons with different transverse dimensions in a noncentrosymmetric photorefractive crystal is studied both in theory and in experiment. An anomalous incoherent interaction between one- and two-dimensional solitons, whose attractive and repulsive effects depend on the soliton separation, is numerically demonstrated by employing an anisotropic model. By launching a one-dimensional green beam and a two-dimensional red beam into a biased SBN:60 crystal, the hybrid-dimensional soliton interaction is performed. The experimental results are in good agreement with the numerical ones.展开更多
We investigate the co-propagation of a strong pump beam and a weak signal beam in lead glass, and find that the large phase shift of the strongly nonlocal spatial optical soliton (SNSOS) can be realized via cross-ph...We investigate the co-propagation of a strong pump beam and a weak signal beam in lead glass, and find that the large phase shift of the strongly nonlocal spatial optical soliton (SNSOS) can be realized via cross-phase modulation. The theoretical study suggests a synchronous propagation of the pump SNSOS and the signal SNSOS under the required initial condition. A π-phase shift of the signal SNSOS is experimentally obtained by changing the power of the pump SNSOS by about 13 mW around the soliton critical power, which agrees qualitatively with our theoretical prediction. The ratio of the phase shift rate of the signal SNSOS to that of the pump SNSOS shows a close match to the reciprocal of the ratio between their wavelengths.展开更多
Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition induced by a magnetic field directed along the axis of anisotropy, while the additional action of high-frequency field perpendicu...Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition induced by a magnetic field directed along the axis of anisotropy, while the additional action of high-frequency field perpendicular to the main magnetic field, are analyzed. It is shown that the spatial motion of solitons, associated with thermal fluctuations in the crystal, does not destroy the equilibrium of self-organized PBS.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 60508005), and Scientific Research Foundation of Harbin Institute of Technology of China (Grant No HIT. 2003. 31).
文摘This paper predicts that grey spatial solitons can exist in two-photon photorefractive materials. In steady state and undcr appropriate external bias conditions, it obtains the grey spatial soliton solutions of the optical wave evolution equation. The intensity profile, phase distribution, and transverse velocity of these grey solitons are discussed.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10474023 and 10674050) and Specialized Research Fund for the Doctoral Program of Higher Education (Grant No 20060574006).
文摘The fundamental and second order strongly nonlocal solitons of the nonlocal nonlinear Schrodinger equation for several types of nonlocal responses are calculated by Ritz's variational method. For a specific type of nonlocal response, the solutions of the strongly nonlocal solitons with the same beam width but different degrees of nonlocality are identical except for an amplitude factor. For a nonlocal case where the nonlocal response function decays in direct proportion to the mth power of the distance near the source point, the power and the phase constant of the strongly nonlocal soliton are in inverse proportion to the (m + 2)th power of its beam width.
基金Project supported by the Major Program of the National Natural Science Foundation of China (Grant No 10674176)
文摘This paper studies numerically the dark incoherent spatial solitons propagating in logarithmically saturable nonlinear media by using a coherent density approach and a split-step Fourier approach for the first time. Under odd and even initial conditions, a soliton triplet and a doublet are obtained respectively for given parameters. Simultaneously, coherence properties associated with the soliton triplet and doublet are discussed. In addition, if the values of the parameters are properly chosen, five and four splittings from the input dark incoherent spatial solitons can also form. Lastly, the grayness of the soliton triplet and that of the doublet are studied, in detail.
基金Project supported by the National Natural Science Foundation of China (Grant No 10574051).
文摘The dynamical evolution and stability of bright dissipative holographic solitons in biased photorefractive materials in which the self-trapping beam obtains a gain from the pump beam via two-wave mixing has been investigated numerically. Results show that these solitons are stable relative to small perturbations. Adjusting some system parameters, such as the bias field and the angle between beams, can easily control the generation of such solitons. Potential applications in optical switches or repeaters are discussed.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10474023 and 10674050)the Specialized Research Fund for the Doctoral Program of Higher Education, China (Grant No 20060574006)the Program for Innovative Research Team of the Higher Education in Guangdong Province of China (Grant No 06CXTD005)
文摘We study the propagation of (l+l)-dimensional spatial soliton in a nonlocal Kerr-type medium with weak non- locality. First, we show that an equation for describing the soliton propagation in weak nonlocality is a nonlinear Schr6dinger equation with perturbation terms. Then, an approximate analytical solution of the equation is found by the perturbation method. We also find some interesting properties of the intensity profiles of the soliton.
文摘The purpose of this paper is to present an all-optical EXOR for cryptographic application based on spatial soliton beams. The device is based on the propagation and interactions properties of spatial soliton in a Kerr nonlinear material. The interaction force between parallel soliton beam is analyzed from the analytical point of view and an exact solution is presented.
基金Supported by the Science Research Foundation of Shunde Polytechnic under Grant No. 2008-KJ06Supported by the NPRP 25-6-7-2 Project with the Qatar National Research Foundation
文摘We study analytically and numerically the propagation of spatial solitons in a two-dimensional stronglynonlocal nonlinear medium. Exact analytical solutions in the form of self-similar spatial solitons are obtained involvinghigher-order Hermite-Gaussian functions. Our theoretical predictions provide new insights into the low-energy spatialsoliton transmission with high fidelity.
基金National Basic Research Program of China under Grant No.2006CB921605the Science Research Foundation of Shunde College of China
文摘Collisions of spatial solitons occurring in the nonlinear Schringer equation with harmonic potential arestudied,using conservation laws and the split-step Fourier method.We find an analytical solution for the separationdistance between the spatial solitons in an inhomogeneous nonlinear medium when the light beam is self-trapped inthe transverse dimension.In the self-focusing nonlinear media the spatial solitons can be transmitted stably,and theinteraction between spatial solitons is enhanced due to the linear focusing effect (and also diminished for the lineardefocusing effect).In the seff-defocusing nonlinear media,in the absence of seff-trapping or in the presence of linearself-defocusing,no transmission of stable spatial solitons is possible.However,in such media the linear focusing effectcan be exactly compensated,and the spatial solitons can propagate through.
基金Supported by the Science and Technology Development Foundation of Higher Education of Shanxi Province under Grant No.200611042 Basic Research Foundation of Yuncheng University under Grant No.JC-2009003
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10574051 and 10174025) and the Research Foundation for 0utstanding Young Teachers, China University of Geosciences (Grant No CUGQNL0621).
文摘We investigate theoretically the temperature effects on the evolution and stability of a separate screening brightdark soliton pair formed in a serial non-photovoltaic photorefractive crystal circuit. Our numerical results show that, for a stable bright-dark soliton pair originally formed in a crystal circuit at given temperatures, when one crystal temperature changes, the soliton supported by the other crystal will evolve into another stable soliton if the temperature change is quite small, whereas it will become unstable and experience larger cycles of compression or break up into beam filaments if the temperature difference is big enough. The dark soliton is more sensitive to the temperature change than the bright one.
基金Supported by the National Natural Science Foundation of China under Grant No 10474136.
文摘We investigate theoretically waveguides induced by screening-photovoltaic solitons in biased photorefractive-photovoltaic crystals. We show that the number of guided modes in a waveguide induced by a bright screening photovoltaic soliton increases monotonically with the increasing intensity ratio of the soliton, which is the ratio between the peak intensity of the soliton and the dark irradiance. On the other hand, waveguides induced by dark screening-photovoltaic solitons are always single mode for all intensity ratios and the confined energy near the centre of a dark screening-photovoltaic soliton increases monotonically with the increasing intensity ratio. When the bulk photovoltaic effect is neglectable, these waveguides are those induced by screening solitons. When the external field is absent, these waveguides predict those induced by photovoltaic solitons.
基金Supported by the National Natural Science Foundation of China under Grant No 10174025, and the Key Foundation of the Education Ministry of China under Grant No 011118.
文摘The dynamics evolution of dark holographic solutions in a dissipative system is investigated numerically provided that the double balance, i.e. diffraction is balanced by nonlinearity and loss is balanced by gain, is satisfied. The influence of the system parameters, such as the linear loss of the crystal, the external biased field and the angel between input beams, on the stable propagation of soliton beams is discussed numerically. Results show that such solitons can be easily amplified or absorbed by adjusting these system parameters. Furthermore, numerical simulations indicate that dissipative dark holographic solitons are stable for small perturbation on amplitude.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10574051 and 10174025).
文摘The dynamical evolution of both signal and pump beams are traced by numerically solving the coupled-wave equation for a photorefractive two-wave mixing system. The direct simulations show that, when the intensity ratio of the pump beam to the signal beam is large enough, the pump beam presents a common decaying behaviour without modulational instability (MI), while the signal beam can evolve into a quasistable spatial soliton within a regime in which the pump beam is depleted slightly. The larger the ratio is, the longer the regime is. Such quasistable solitons can overcome the initial perturbations and numerical noises in the course of propagation, perform several cycles of slow oscillation in intensity and width, and persist over tens of diffraction lengths. From physical viewpoints, these solitons actually exist as completely rigorous physical objects. If the ratio is quite small, the pump beam is apt to show MI, during which the signal beam experiences strong expansion and shrinking in width and a drastic oscillation in intensity, or completely breaks up. The simulations using actual experimental parameters demonstrate that the observation of an effectively stable soliton is quite possible in the proposed system.
基金Project supported by the Special Funds of the National Natural Science Foundation of China(Grant No.11247313)
文摘By using semiclassical theory combined with multiple-scale method, we analytically study the linear absorption and the nonlinear dynamical properties in a lifetime broadened Λ-type three-level self-assembled quantum dots. It is found that this system can exhibit the transparency, and the width of the transparency window becomes wider with the increase of control light field. Interestingly, a weak probe light beam can form spatial weak-light dark solitons. When it propagates along the axial direction, the soliton will transform into a steady spatial weak-light ring dark soltion. In addition, the stability of two-dimensional spatial optical solitons is testified numerically.
基金supported by the National Natural Science Foundation of China(Grant No.61308019)the Foundation for Distinguished Young Talents in Higher Education of Guangdong Province,China(Grant No.Yq2013157)
文摘A theory is presented to investigate the existence and propagation stability of gap solitons in a parity-time (PT) com- plex superlattice with dual periods. In this superlattice, the real and imaginary parts are both in the form of superlattices with dual periods. In the self-focusing nonlinearity, PT solitons can exist in the semi-infinite gap. However, only those gap solitons with low powers can propagate stably, whereas the high-power solitons present periodic oscillation and simultane- ously suffer energy decay. In the self-defocusing nonlinearity, PT solitons only exist in the first gap and all these solitons are stable.
基金Project supported by the Dongguan Science and Technology Program,Guangdong Province,China(Grant No.200910814038)
文摘The existence of one-dimensional bright Kerr solitons is investigated in Kerr media beyond the paraxial approximation. It is found that a nonparaxial soliton with no less than a minimum dimensionless width of about 0.76 can exist, which corresponds to the real width about a wavelength. Besides, the coherent interactions between two nonparaxial bright solitons in Kerr media are also investigated in detail. It is found that their separation and intensity ratio have great influence on the coherent interaction between these two solitons. Furthermore, the effect of the relative phase difference on the nonparaxial interaction is quite different from that on the paraxial interaction. Periodical breath, merging, repulsion, and energy transferring can be realized separately by choosing an appropriate initial relative phase between the coherent solitons.
基金Project supported by the Doctoral Science Foundation of Northwestern Polytechnical University (NPU),China (Grant No. CX200514)the NPU Foundation for Fundamental Research,China
文摘The incoherent interaction between solitons with different transverse dimensions in a noncentrosymmetric photorefractive crystal is studied both in theory and in experiment. An anomalous incoherent interaction between one- and two-dimensional solitons, whose attractive and repulsive effects depend on the soliton separation, is numerically demonstrated by employing an anisotropic model. By launching a one-dimensional green beam and a two-dimensional red beam into a biased SBN:60 crystal, the hybrid-dimensional soliton interaction is performed. The experimental results are in good agreement with the numerical ones.
基金Project supported by the National Natural Science Foundation of China(Grant No.11274125)
文摘We investigate the co-propagation of a strong pump beam and a weak signal beam in lead glass, and find that the large phase shift of the strongly nonlocal spatial optical soliton (SNSOS) can be realized via cross-phase modulation. The theoretical study suggests a synchronous propagation of the pump SNSOS and the signal SNSOS under the required initial condition. A π-phase shift of the signal SNSOS is experimentally obtained by changing the power of the pump SNSOS by about 13 mW around the soliton critical power, which agrees qualitatively with our theoretical prediction. The ratio of the phase shift rate of the signal SNSOS to that of the pump SNSOS shows a close match to the reciprocal of the ratio between their wavelengths.
文摘Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition induced by a magnetic field directed along the axis of anisotropy, while the additional action of high-frequency field perpendicular to the main magnetic field, are analyzed. It is shown that the spatial motion of solitons, associated with thermal fluctuations in the crystal, does not destroy the equilibrium of self-organized PBS.