共查询到19条相似文献,搜索用时 78 毫秒
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有均匀芯区场三层任意幂次非线性平板光波导 总被引:1,自引:1,他引:0
研究了芯区和包层的非线性介电常数具有相同形式ε∝|E|^δ的光波导,其中E为本地电场强度,δ可以为任意正数。结果表明,在适当的光强下有5种结构芯区电场分布可以变为均匀场,而且强非线性的介质有利于在较低光功率下产生均匀的芯区场。δ=2时(Kerr型介质,其结构与我们的前期工作一致。 相似文献
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在理论上证实了采用双相位干涉法直接测定光折晶体内折射率光栅相对于光强分布的相位移和非线性介质三次非线性极化率相位的可能性。 相似文献
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聚焦光学系统光学限制效应的分析 总被引:2,自引:0,他引:2
本文利用高斯分解法给出了聚焦光学系统中光学非线性介质引起的光学限制效应,以及几何排布对其的影响。结果表明,近场几何排布下的光学限制效应十分不同于远场情况。具有正非线性系数的介质是不能用来做光学限制介质的。 相似文献
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富勒烯分子LB膜三次非线性光学性质研究 总被引:2,自引:1,他引:1
在C60花生酸复合LB膜中实现了立体简并四波混频和多重前向光学相位共轭输出,观察到了共轭光输出的累积效应,采用相对测量法测得C60LB膜的X(3)为(1.8±0.4)×10-8esu,分析了前向共轭光强与信号光、泵浦光强的关系,最后讨论了非线性效应产生的原因. 相似文献
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掺杂非线性吸收介质的光子晶体的双稳态特性 总被引:3,自引:1,他引:2
从光子晶体的传输矩阵理论出发,推导了掺杂饱和吸收非线性介质的光子晶体的缺陷模的透射率,以及缺陷层中局域光的增强因子。计算表明,基于非线性介质透过率的感应变化和透过率的正反馈作用,掺杂非线性吸收介质的一维光子晶体具有双稳态特性;实现双稳态所需的入射光强阈值决定于光子晶体的折射率参数、掺杂介质的饱和吸收光强,并随光子晶体的周期数N的增大而指数减小。 相似文献
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近年来对含有非线性介质环形腔透射率的双稳态与混沌行动的研究甚多。主要有:(1)入射光频率与吸收介质频率共振,当输入光强变化时,透射光强表现出双稳态和自脉动现象;(2)入射光的频率与吸收介质的频率为失谐,当输入光强增加时,透射光强呈现多稳,失稳和混沌行为,这些已有不少实验验证。 相似文献
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直接从负折射介质中包含高阶色散及饱和非线性效应的扩展非线性传输方程出发,采用线性稳定性分析法和德鲁德电磁模式,导出了调制不稳定性的色散关系和增益谱公式。考虑到今后的实验验证,以实际单位的形式计算了方程系数随归一化角频率的变化规律。再以实际单位的形式计算并讨论了增益谱随归一化角频率和归一化入射光强的变化关系。结果表明,当归一化角频率固定时,截止频率及峰值增益都随归一化入射光强的增加先增加后减少,归一化角频率不同,截止频率及峰值增益也不同,在靠近禁带处,增益谱远离零点。当归一化入射光强固定时,截止频率及峰值增益随归一化角频率的增加而增加,当归一化角频率增大到靠近禁带时,增益谱由紧挨零点变成远离零点。 相似文献
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近场超分辨纳米薄膜结构可以突破衍射极限实现纳米尺寸信息存储,是下一代海量存储技术的重要方案之一,也是纳米光子学研究中的热点.纳米膜层结构基于激光作用下的非线性局域光学效应实现超分辨.分析了超分辨近场薄膜结构突破衍射极限的光学原理,对超分辨纳米薄膜结构的表面等离子体激发特性、非线性光学特性、近场光学特性和超透镜效应等重要光学性质的最新研究进展做了系统介绍. 相似文献
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Nonlinearity-Compensation-Free Optical Frequency Domain Reflectometry Based on Electrically-Controlled Optical Frequency Sweep 下载免费PDF全文
A nonlinearity-compensation-free optical frequency domain reflectometry (OFDR) scheme is proposed and experimentally demonstrated based on the electrically-controlled optical frequency sweep. In the proposed scheme, the linear frequency sweep light is generated by propagating an ultra-narrow-linewidth continuous-wave (CW) light through an electro-optic frequency shifter which consists of a dual-parallel Mach-Zehnder modulator (DPMZM) and an electronic 90° hybrid, where the electro-optic frequency shifter is driven by a linear frequency modulated signal generated by a direct digital synthesizer (DDS). Experimental results show that the spatial resolution and signal-to-noise ratio (SNR) of the proposed OFDR scheme without the nonlinear phase compensation are comparable to those of OFDR employing a commercial tunable laser source (TLS), an auxiliary interferometer, and a software-based nonlinear phase compensation method. The proposed OFDR scheme is helpful to reduce the complexity of the optical structure and eliminate the difficulty of developing the nonlinear phase compensation algorithm. 相似文献
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A theoretical demonstration of optical bistability in periodic layered media, particularly in long-period GaAs/AlAs superlattices is presented. The proposed structure consists of a periodic multilayer system, as opposed to previously demonstrated nonlinear bistable devices which employed Fabry-Perot etalons. The optical resonance effect which is essential for bistable devices is, in this case, induced by a refractive index modulation. The nonlinear active medium is distributed in the whole structure rather than placed between the two mirrors of a Fabry-Perot cavity. It is shown by a complete calculation of wave propagation in the periodic nonlinear medium that a multiple valued feature appears in the structure's nonlinear reflectivity spectrum. The input/output characteristics of the structure exhibit bistable hysteresis similar to that of a nonlinear Fabry-Perot etalon 相似文献
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In the nonlinear directional coupler, the optical field and the nonlinear material usually interact in a spatially and temporally local fashion and the device exhibits a nonlinear transmission characteristics, but it is not bistable. In this paper, it is shown theoretically that optical bistability in the input optical power is possible for the nonlinear directional coupler if the local phase change of the optical mode propagating through tile coupler is influenced by the excitation over the whole coupler. This condition can be satisfied in a coupler based on biased-pin-diodes comprising coupled asymmetric quantum wells in the i-region, Calculations show that in this configuration, the nonlinear directional coupler can exhibit sharp switching characteristics, low switching optical powers, optical bistability or bifurcation 相似文献
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介绍了用于光纤通信非线性补偿中的几种非线性光环路镜(NOLM,包括ANOLM、DALM、NALM、DILM、RA-NOLM、NBLM及DANLM)的构成和功能,给出了部分传输补偿实例,指出NOLM的发展趋势是小型化和集成化。 相似文献
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Optical limiting in GaAs 总被引:3,自引:0,他引:3
Boggess T. Smirl A. Moss S. Boyd I. Van Stryland E. 《Quantum Electronics, IEEE Journal of》1985,21(5):488-494
We have used two-photon absorption, self-defocusing, and optically-induced melting in GaAs to limit 1 μm picosecond pulsed radiation. The contribution to the limiting action from each of these mechanisms is discussed and demonstrated. Additionally, we measure a two-photon absorption coefficient of 26 cm/GW, which is in good agreement with the smallest values reported in the literature. A pulse-width study of the nonlinear absorption was conducted to isolate the effects of two-photon-generated free-carrier absorption. Results indicate that, even though the number of free-carriers is sufficient to severely defocus the incident beam, free-carrier absorption does not measurably contribute to the nonlinear absorption. 相似文献