共查询到20条相似文献,搜索用时 78 毫秒
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周海光 《红外与毫米波学报》2002,21(Z1):112-114
对布满液晶微粒的聚合物(PDLC)进行了简并四波混频及光学双稳态的研究,并在文中对相关的PDLC中的分子重取向和热效应的非线性光学效应进行了讨论. 相似文献
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光纤通信系统中四波混频的分析 总被引:1,自引:0,他引:1
随着光纤通信系统容量的增加和无中继传输距离的延长,DWDM及EDFA的使用,光纤中的四波混频现对通象信系统性能的影响越来越受到重视,本论述了四波混频的发生机理。并分析了四波混频对通信性能的影响,以及如何运用各种技术抑制通信光纤中的四波混频。同时讨论了利用四波混频产生的新频率光可以制作多种光通信器件。 相似文献
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本文从四波混频的基本方程出发,采用量子方法推导了在四波混频情况下产生压缩态的基本结果,得到了压缩系数与四波混频介质的非线性极化 相似文献
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用液晶分子运动的动力学方程,求出了激光诱导向列相液晶分子重新取向的取向角、折射率改变、阈值场强和上升时间的近似表达式。讨论了它们随液晶材料参数、激光强度和激光在液晶中传播方向的变化,进行了数值计算。给出了激光能诱导向列相液晶分子重新取向的必备条件,得到向列相液晶的各向异性是其分子重新的取向的根本原因。 相似文献
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We have studied the mechanism and the dynamics of degenerate four-wave mixing in a nematic liquid crystal film. Nanosecond laser pulses are used to generate an index grating associated with the changes in the density and in the order parameter. We have measured and analyzed the contributions from these two mechanisms, their interference effects rise and decay time constants, and have also performed a detailed analysis of the diffraction efficiency. This study quantitatively characterizes the potential usefulness of nematie films for four-wave mixing based applications. 相似文献
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手征向列相(N*)液晶能够选择性反射入射光,但其反射波宽一般小于150nm。利用负介电各向异性的向列相液晶SLC10V513-200与手性化合物R1011、CB15配制出5种N*液晶,其反射波长能够覆盖整个可见光波段。使用异佛尔酮二异氰酸酯(IPDI)界面聚合法制备出平均粒径为8.0μm的5种N*液晶聚脲微胶囊之后,将相同质量的5种微胶囊混入OP-10与IPDI中制备出微胶囊的凝胶。对80.0μm厚微胶囊凝胶薄膜施加交流电场,使微胶囊中的液晶处于平面织构状态,紫外固化微胶囊中的液晶性单体,固定微胶囊中N*液晶的平面织构,从而制备出可以反射可见光波段的微胶囊凝胶薄膜。 相似文献
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一、引言 相干反斯托克斯喇曼散射光谱(CARS)作为一种研究分子结构的手段,已在物理、化学、生物学以及相关的一些技术领域获得令人鼓舞的应用。它是基于两个和分子体系相作用的光波其频率差ω_1-ω_2和相应分子的振动模ω-r共振,对频率为ω_(as)=2ω_1-ω_2的四波混频光信号强度I_(as)的增强来获取该分子的振动结构信息的(图1(a))。当入射光束ω_2有较宽的频带结构,并满足ω_1-ω_2=ω_r的条件下,视分子振动模频率的不同,将有多条ω_(as)谱线同时出现, 相似文献
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顾洪恩 《红外与毫米波学报》1991,10(1):5-9
利用简并四波混频技术观测到LiF晶体中F_3~+色心的非线性光学相位共轭效应,以脉冲染料激光为泵浦光得到最大相位共轭反射率约为0.1%,根据LiF晶体F_3~+色心的能级特点从理论上阐明了F_3~+色心系统非线性饱和吸收和四波混频的物理起源。 相似文献
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报道了国产向列型液晶MBBA和EBBA的Raman谱与温度的关系。提出了一种适用于取向的向列型液晶分子振动相关函数和转动相关函数的分离理论。此理论应用于MBBA液晶相和液相的分子振动和转动弛豫的实验研究表明这种分离方法是可行的。 相似文献
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Fast and high‐contrast responses with low driving voltages in twisted nematic (TN) cells are achieved for anisotropically oriented structures of liquid‐crystalline physical gels. They are prepared by hydrogen‐bonded aggregation of an L ‐lysine‐based gelator in nematic liquid crystals. When the mixtures of the nematic liquid crystals and the gelator are prepared in TN cells, fibrous aggregates of the gelator align along the twisted‐nematic orientation of the liquid crystal, forming oriented phase‐separated structures. 相似文献
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Higher-order diffraction components have been observed from the phase volume grating formed in photorefractive crystals Bi12GeO20 via degenerate four-wave mixing. Brief explanations based on the conventional grating theory and the dynamic theory of volume holography are given. 相似文献
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Fascinating nematic‐ and smectic‐like self‐assembled arrays are observed for gold nanorods partially capped with either laterally or terminally attached nematic liquid crystals upon slow evaporation of an organic solvent on TEM grids. These arrays can be manipulated and reoriented by applying an external magnetic field from quasi‐planar to vertical similar to a Fréedericksz transition of common organic nematic liquid crystals. Birefringence and thin film textures of these self‐assembled gold nanorod arrays observed by polarized optical microscopy are strongly reminiscent of common organic nematic liquid crystal textures between crossed polarizers and, additionally, support the formation of ordered liquid crystal‐like anisotropic superstructures. The ordering within these arrays is also confirmed in bulk samples using small angle X‐ray scattering (SAXS). 相似文献