非线性光学材料

对光折变有机聚合物中的双色光空间孤子进行了理论分析,证明双色信号光的两个频率成分相互作用可以在折射率改变为正的光折变有机聚合中形成暗暗和亮暗空间孤子,在折射率改变为负的光折变有机聚合物中形成亮亮和亮暗空间孤子。与单色光孤子的情况不同,对于双色光孤子情况,通过与一形成暗孤子的频率成分相互作用,另一频率成分在折射率改变为正的有机聚合     

双色光光伏空间孤子的形成条件及其应用

以折射率改变为正的光伏晶体为例，讨论在其中形成双色光光伏空间孤子的条件-一般而言，在满足上述条件的情况下，双色光可以形成双色光亮孤子、双色光暗孤子、一亮一暗孤子-对于一个波长的光（ray2）单独不能形成亮孤子（它的Glass系数与背景光的Glass系数之比R2小于１）的情况，如果再加上一束另一个波长的光（ray1），且其Glass系数与背景光的Glass系数之比R1大于１，则在一定条件下，这个双色光中两个颜色的光可以都形成亮孤子-还讨论了ray1的光强对孤子宽度的影响- 关键词： 双色光 光伏 空间孤子 全光开关     

闭路光伏光折变聚合物中非相干耦合亮-暗空间孤子对

为了得到闭路光折变有机聚合物中存在非相干耦合亮-暗光伏空间孤子对,采用数值模拟的方法,对稳态情况下两束互不相干的光束,在闭路光伏光折变有机聚合物中的传播进行了研究。结果表明,具有相同偏振和相同波长的两束互不相干的光束,可在光伏光折变有机聚合物中形成非相干耦合亮-暗光伏孤子对。在给定适当参量或扰动不太大的情况下,孤子对中的亮孤子和暗孤子都能在光伏光折变有机聚合物中稳定传播。研究结果可为光折变有机聚合物空间孤子理论的发展提供理论依据。     

折射率改变为正的光折变晶体中形成一维光伏暗孤子

提出了一个考虑背景光光伏效应贡献的光伏孤子理论,它指出在折射率变化为正的晶体中,既可产生光伏亮孤子,也可产生光伏暗孤子.当背景光对信号光的有效Glass系数之比为R小于1时,孤子是亮的;R大于1时,孤子是暗的.对亮孤子而言,R值越大,孤子越宽,而对暗孤子,R值越大,孤子越窄.当R为1时,不能形成光伏孤子.一维暗孤子实验结果与理论一致. 关键词： 光折变空间孤子 光伏孤子 暗孤子 正折射率改变     

外加电场光折变有机聚合物串联回路中独立空间孤子对

对外加电场光折变有机聚合物串联回路中独立空间孤子对进行了理论研究,导出了在光折变有机聚合物串联回路中两光束传播的耦合方程,证明了串联回路中存在暗-暗、明-暗和明-明三种独立空间孤子对.在光束的空间展宽远小于有机聚合物宽度的极限条件下,暗-暗孤子对之间孤子入射光强的改变可相互影响到对方的包络和动态演化.对于明-暗孤子对,暗孤子通过光电流能影响明孤子,但明孤子不能影响暗孤子.明-明孤子对之间没有影响. 关键词： 非线性光学 光折变效应 光折变聚合物 空间孤子对     

中心对称光折变晶体中非相干耦合空间孤子族

 为了得到中心对称光折变晶体中存在非相干耦合空间孤子族的结果,基于中心对称光折变晶体空间孤子的基本理论,推导出了中心对称光折变晶体中非相干耦合亮、暗和亮-暗混合空间孤子族空间归一化包络解的积分形式,并对其特性进行了数值模拟。结果表明：这种孤子族是由多束偏振方向和波长都相同的互不相干的光束耦合形成的,非相干耦合孤子族在中心对称光折变晶体中传播时,各分量成分光束都能稳定传播,当入射光束中只含有两分量时,空间孤子族退化为暗 暗、亮-亮和亮-暗空间孤子对。     

光折变有机聚合物中的空间孤子

给出了稳态情况下光折变聚合物中光波演化方程的亮、暗及灰孤子解,并讨论了不同孤子态的偏振特性及孤子宽度与外加电场的关系. 关键词： 光折变 聚合物 空间孤子     

暗-暗与亮-暗光伏孤子相互作用

用数值方法分析了平行传播异色光伏暗孤子之间及亮-暗孤子之间的相互作用.结果表明，光伏暗孤子共轴传播能在有限的距离内保持准孤子形态，靠近传播时存在着相互吸引的作用 ，而相距较远传播时表现为一孤子暗区使另一孤子的缓变光场部分发生局部会聚作用.光伏暗孤子与亮孤子的相互作用随距离的不同可使亮孤子光强分布变尖锐或变平缓，以及使亮孤子发生能量转移.从两束信号光共同引起折射率波导这一物理机理对光伏孤子这些相互作用给出定性物理解释. 关键词： 光伏空间孤子 暗孤子 亮孤子 相互作用     

双光子光折变介质中的非相干耦合空间孤子对

对双光子光折变晶体中两束偏振方向和波长都相同的互不相干光束的耦合进行了研究, 预言了非相干耦合暗-暗、亮-亮及亮-暗双光子空间孤子对的存在. 关键词： 双光子光折变效应 光折变材料 空间孤子     

光折变聚合物中的小振幅空间光孤子

给出了稳态条件下光折变聚合物中的小振幅空间孤子的演化方程,得到了方程的暗、亮孤子解析解,并且给出了小振幅聚合孤子的宽度表达式结果表明,光折变聚合物中存在着双曲正切形式的小振幅暗空间孤子和双曲正割形式的小振幅亮空间孤子,小振幅聚合孤子的宽度与外加电场成反比关系.     

Effect of the dark soliton crystal temperature on the deflection of the bright soliton in a separate bright–dark screening soliton pair

We investigate theoretically the dark soliton crystal temperature effect on the deflection of the bright one in a bright–dark soliton pair which is formed in a serial non-photovoltaic photorefractive crystal circuit. Our numerical results show that the spatial shift of the bright soliton changes with the temperature of the dark one crystal and varying the temperature of the dark soliton crystal can influence the deflection strongly. The temperature dependence of the deflection process is further studied by perturbation technique and the results are found to be good agreement with that obtained by numerical method. Relevant examples are provided.     

光折变晶体中光诱导波导的折射率分布

分别讨论了亮孤子和暗孤子在光折变晶体中诱导波导的折射率分布,结果表明光诱导波导的折射率分布除与光强的倒数有关外,还与光强对数的一阶导数有关.后者对折射率的影响引起波导折射率的非对称性分布.     

Dark and bright photovoltaic spatial solitons in photorefractive crystals with positive refractive-index perturbation

We have demonstrated, for what is believed to be the first time, that in a photorefractive crystal with positive refractive-index perturbation a two-dimensional dark or bright photovoltaic spatial soliton can be formed in the same crystal by a signal beam and a background beam of different wavelengths. We discuss the conditions on the effective Glass constants and the absorption coefficients of the background and signal beams in determining the formation of the spatial soliton.     

Temperature effects of Hamiltonian dark solitons on the stability of holographic solitons in a separate holographic–Hamiltonian soliton pair

We investigate theoretically the temperature effects on the evolution and stability of a separate holographic–Hamiltonian dark–dark or bright–dark soliton pair formed in an unbiased serial photorefractive crystal circuit. Our numerical results show that, for a stable dark–dark or bright–dark soliton pair originally formed in a crystal circuit at given temperatures, when the crystal in which formed a Hamiltonian dark soliton changes, the holographic dark or bright soliton supported by the other crystal tends to evolve into another stable soliton or experiences larger cycles of compression or breaks up into beam filaments or exhibit a common decaying process. The holographic dark soliton is more sensitive to the temperature change than the holographic bright one.     

Separate Holographic-Hamiltonian screening soliton pairs in a biased series photorefractive crystal circuit

Separate Holographic-Hamiltonian screening soliton pairs are predicted in a biased series photorefractive crystal circuit consisting of two photorefractive crystals connected electronically by electrode leads in a chain with a voltage source. The existence of four types of the separate soliton pairs: dark–dark, bright–dark, dark–bright and bright–bright in such a circuit is proved. Under the limit in which the spatial extent of the optical wave is much less than the width of the crystal, the Hamiltonian dark soliton can affect the other soliton by the light-induced current whereas the Hamiltonian bright soliton and holographic soliton cannot affect the other soliton in the soliton pair.     

Effects of dark soliton crystal temperature on the self-deflection of bright soliton in a biased serial photovoltaic photorefractive crystal circuit

Based on the theory of one-dimensional separate soliton pairs formed in a serial photovoltaic photorefractive crystal circuit, the effects of the dark soliton crystal temperature on the self-deflection of the bright one in a bright-dark soliton pair are investigated. The numerical results indicate that the spatial shift of the bright soliton can experience obvious increase in their self-deflection with the increase of the temperature of the dark soliton. The self-bending process is further studied using perturbation techniques and the results are found to be good agreement with that obtained by numerical method.     

Incoherently coupled spatial soliton families in photorefractive polymers

It is shown theoretically that incoherently coupled bright or dark spatial soliton families can be realized in biased guest-host photorefractive polymers under steady-state conditions. These soliton families can be established provided the multiple carrier beams share the same polarization, wavelength, and are mutually incoherent. These soliton families will reduce to soliton pairs when they contain only two components. Moreover, the stability of such soliton families has been discussed by the numerical method.     

Photovoltaic solitons in two-photon photorefractive materials under open-circuit conditions

We present the evolution equation of one-dimensional spatial soliton in two-photon photorefractive media under open-circuit conditions. In the steady state regime, our solutions show that the dark and bright photovoltaic spatial solitons can be supported in two-photon photorefractive media under open-circuit conditions.