Liquid cryatal discover and develop history are introduced in the first part . at the same time , the most study content of liquid crystal physics and the significance of study the temperature effect of voltage - dependent birefringence 第一章简要介绍了液晶发现地展的历史和液晶物理学的研究内容并叙述了研究液晶电控双折射率温度效应的意义
We can see from the formula 8 = ? 2 n d ( ne - n0 ) / x that the retardation will be independent on wavelength if the refraction indices have direct ratio to wavelength , then we will get the achromatic optical phase retarders 根据关系式2 d ( n _ e - n _ o )可知，如果材料的双折射率与波长成正比，延迟量便与波长无关，即可获得消色差相位延迟器。
Usually , a large birefringence change ( 0 . 2 ) can be achieved by a relatively small voltage ( a few volts , depending on the lc used ) . its wavelength tenability is determined by the controlled birefringence of the liquid crystal used 通常，较小的电压( 0 - 3伏)就足以产生较大的双折射率的变化( 0 . 2 ) ，具体的电压值由所用液晶材料决定。 ( 3 )双折射率连续可调。
When we applied electric field , the the oritation of liquid crystal molecule axis reset . it induced the roate of optic axis . at last , the birefringence will change . this is the voltage - dependent birefringence of liquid 例如当对液晶施加电场时，液晶分子轴的排列会变化，从而引起液晶光轴的转动，最终导致了液晶双折射率的变化，这就是我们所说的液晶电控双折射特性。
Through measuring the thickness of mica plates and the wavelengths at which they act as quarter wave phase retarders , the birefringence can be obtained in terms of the function relation between the phase delay , the wavelength and the thickness 通过测量云母材料的厚度和相应厚度情况下作为/ 4波片使用所对应的波长，利用相位延迟与波长及厚度函数关系式直接求得云母的双折射率。
It is proved that it has many attractive features ( 1 ) its applicable spectral range is broad , many liquid crystals have very large birefringence and good transparency in both near ultraviolet band , visible band and infrared band 本文重点研究了可调谐液晶电光滤光片，它的主要优点有： 1 、可应用的光谱范围特别宽。许多液晶在紫外、可见光、红外都具有较大的双折射率和良好的透射性。
There are many factor affecting voltage - dependent birefringence . but the temperature effect of voltage - dependent birefringence cannot ignore in the course of liquid crystal device design and production . this thesis mostly study the regularity of voltage - dependent birefringence with charging the temperature 影响液晶电控双折射率的因素很多，但是，在液晶器件设计、制作中，液晶的电控双折射率温度效应通常是不能忽略的。
The refractive indices at 12 wave lengths in the visible region were measured with the minimum deviation method , showing that kabo is a negative uniaxial optical crystal with moderate birefringence . the measurement of nonlinear optical coefficient dn = 0 . 45pm / v 用最小偏离法测试了可见光区十二个波段处的晶体折射率，结果表明kabo晶体属负单轴晶，具有适中的双折射率。晶体的非线性光学性质测试显示，该晶体非线性光学系数为d _ ( 11 ) = 0 . 45pm / v ，可实现相位匹配。
The tunable performance is obtained by rotating the grating . the disadvantages of the mechanical tunable filter are high control voltage , slow response time and big volume . the electro - optic tunable filters are obtained by the alteration of the birefringence of the electro - optic material applied voltage 电子光学滤光片则是通过施加电压使各种电子光学材料的双折射率发生变化来实现透射波长的调谐，也可以利用电光晶体在电场中的旋转来实现波长的调谐。
Conventional optical phase retarders are mostly designed by birefringent material . the refractive indices depend on the wavelength so strongly that the retardation is close to wavelength , here we call this dependent relationship the birefringent dispersion of material . this is the reason why conventional optical phase retarders are mostly applied to a single wavelength but ca n ' t be used to varied wavelength , so they are inconvenient to handle 常规的光相位延迟器是由双折射材料制成的，由于材料的双折射率同波长密切相关，使其产生的相位延迟量也同波长具有严格的一一对应关系(即材料的色散现象) ，因而常规相位延迟片多用于单一波长，不同波长之间使用不可兼顾，这在使用中带来诸多的不便。
