共查询到20条相似文献,搜索用时 78 毫秒
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研究了晶体损耗对屏蔽光伏空间孤子在加偏压的光伏光折变晶体中演化特性的影响.结果表明,损耗除了造成屏蔽光伏孤子光波振幅的减小外,还造成了孤子横截面的改变.对于明孤子,当入射波光强较低时,横截面随传播距离的增长而不断增大;而当入射波光强较高时,起初横截面不断压缩,而后再膨胀,并在某一传播距离上孤子横截面恢复到入射时的尺寸.对于暗孤子,不论入射光孤子光强的高低,横截面都随传播距离的增长而不断增大.虽然在传播距离足够短时,可以不考虑损耗的影响,但距离较大时,损耗将最终导致孤子崩溃.
关键词:
非线性光学
空间光孤子
光折变效应 相似文献
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对有外加电场的双光子光伏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研究,给出产生亮-暗双光子光折变屏蔽光伏孤子对需满足的条件.以Cu:KNSBN晶体作为研究对象,选取α=117.3,β=83.79,η=1.5×10-4,σ=104,δ=0.005,r=10时,给出双光子光折变晶体中的非相干耦合亮-暗屏蔽光伏孤子对2个孤子分量光强的空间分布,证明有外加电场的双光子光伏光折变晶体中存在非相干耦合亮-暗屏蔽光伏孤子对,指出孤子对是由偏振态和波长都相同的两束互不相干光形成的,当外加电场方向和晶体中光伏电场的方向与晶体光轴方向相同时,双光子光折变晶体中可支持亮孤子峰值光强稍大于暗孤子最大光强的非相干耦合亮-暗孤子对,当外加电场方向和晶体中光伏电场的方向与晶体光轴方向相反时,双光子光折变晶体中可支持亮孤子峰值光强稍小于暗孤子最大光强的非相干耦合亮-暗孤子对. 相似文献
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有偏压的光伏光折变晶体中屏蔽光伏孤子的自偏转 总被引:5,自引:2,他引:3
修正了有偏压的光伏光折变晶体中屏蔽光伏孤子的理论。用微扰法研究了屏蔽光伏孤子的自偏转,得出孤子光呸中心的运动为抛物线,并且空间频率分量随传播距离而线性移动,改变外偏压或旋转光的偏振方向可以控制其自偏转。当光伏效应可忽略时,屏蔽光伏孤子的非线性波动方程就转化为屏蔽孤子的非线性波动方程,它的自偏转就转化为屏蔽孤子的自偏转。当外偏压为零时,屏蔽光伏孤子的非线性波动方程就转化为光伏孤子的非线性波动方程,它的自偏转证明了光伏孤子中也存在着自偏转。 相似文献
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LIU Jinsong 《Chinese Journal of Lasers》2001,10(5):347-352
1 Introduction Spatialsolitonsinphotorefractivemediahaveattractedmuchinterestinthepastfewyears[1~ 10 ] .Atpresent,threetypesofscalarsolitons ( quasi steady state[1~ 3 ] ,screening[4~ 8] andphotovoltaicsolitons[9~ 10 ] )havebeen predictedandfound .Sofar ,photovoltaicsolit… 相似文献
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闭路光伏暗空间孤子的自偏转特性研究 总被引:1,自引:2,他引:1
通过考虑扩散效应的影响,采用数值方法,研究了一维稳态闭路光伏暗空间孤子的自偏转特性。结果表明,在扩散项的影响下,光伏暗空间孤子光束的中心沿一个抛物线轨迹在光折变晶体光轴方向上产生偏转;孤子中心偏转距离随光伏场以及入射孤子波强度的增加而单调增加。光伏暗空间孤子与明孤子的自偏转规律有明显不同。 相似文献
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光折变有机聚合物中的双色光空间孤子 总被引:2,自引:4,他引:2
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物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物中也可形成亮孤子;通过与一形成亮孤子的频率成分相互作用,另一频率成分在折射率改变为负的材料中也可形成暗孤子。 相似文献
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Waveguides Induced by Screening-Photovoltaic Solitons in Biased Photorefractive-Photovoltaic Crystals 下载免费PDF全文
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. 相似文献
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A universal theory of steady-state one-dimensional photorefractive spatial solitons is developed which applies to the steady-state one-dimensional photorefractive solitons under various realizations, including the screening solitons in a biased photorefractive medium, the photovoltaic solitons in open- and closed-circuit photovoltaic-photorefractive media and the screening-photovoltaic solitons in biased photovoltaic-photorefractive media. Previous theories advanced individually elsewhere for these solitons can be obtained by simplifying the universal theory under the appropriate conditions. 相似文献
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Effect of temperature on the evolution of bright and dark screening—photovoltaic spatial solitons 下载免费PDF全文
We investigate theoretically the temperature effects on the evolution of both bright and dark screening-photovoltaic optical spatial solitons in biased photovoltaic-photocefractive crystals in the case of neglecting the diffusion process.For a stable bright or dark screening-photovoltaic soliton originally formed in a crystal at a given temperature,when the crystal temperature changes,it will evolve into another stable screening-photovoltaic soliton if the change is quite small,whereas it will become unstable or break down if the temperature change is large enough.The spatial shape of a stable screening-photovoltaic soliton can be reshaped by appropriately adjusting the crystal temperature. 相似文献
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The temporal property of grey screening spatial solitons due to two-photon photorefractive effect in lowamplitude regime is analyzed. The results indicate that a broad solitons is generated at the beginning, and as time evolves, the intensity width of grey solitons decreases monotonically to a minimum value toward steady state. In the same propagation time, the FWHM of solitons decreases with p increasing or m decreasing. Moreover, the formation time of solitons is independent of p and m. The time is close to a constant determined by the dielectric relaxation time. 相似文献
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一维光伏空间灰孤子及其稳定性研究 总被引:4,自引:2,他引:2
从考虑背景光的光伏作用后的光束在光伏媒质中传播的方程出发,证明了在折射率改变为正的光伏媒质中也可以形成灰孤子。光束以灰孤子状态在光伏晶体中传播时,其横向相位必须具有一个与光强分布有关的形式分布,表达式为φ(s)=v[η-∫y^-2(η)dη],其中v是灰孤子的横向运动速度,η是无量纲化坐标,y(η)是归一化的光场振幅。分别讨论了光束灰度、光强振幅、信号光与背景光的有效Glass系数之比R对一维的光伏空间灰孤子宽度、横向总相移和横向运动速度的影响,并分析了光伏灰孤子的稳定性。当光束的灰度m为0时,这一理论可直接退化为光伏暗孤子的理论。 相似文献
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The temporal property of grey screening spatial solitons due to two-photon photorefractive effect in low-amplitude regime is analyzed. The results indicate that a broad solitons is generated at the beginning, and as time evolves, the intensity width of grey solitons decreases monotonically to a minimum value toward steady state. In the same propagation time, the FWHM of solitons decreases with ρ increasing or m decreasing. Moreover, the formation time of solitons is independent of ρ and m. The time isclose to a constant determined by the dielectric relaxation time. 相似文献