Liquid-Crystal Blazed Gratings with Spatially Distributed Pretilt Angle
Liquid-Crystal Blazed Gratings with Spatially Distributed Pretilt Angle
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具有空间分布预倾角的液晶闪耀光栅
DOI：
10.1143/jjap.49.061701
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发表时间：
2010
影响因子：
1.5
通讯作者：
and Susumu Sato
中科院分区：
文献类型：
--
作者：
Michinori Honma;Toshiaki Nose;Satoshi Yanase;Rumiko Yamaguchi;and Susumu Sato
通过引入预倾斜角度的周期性模式，通过调节摩擦密度来控制预倾斜角度，提出了一种电可调谐液晶燃烧光栅。在该光栅中，即使不施加电压，也能实现不对称的分子取向变化。通过调节外加电压来控制衍射光强，在足够高的外加电压下衍射效应消失。得到了不对称的衍射图，并揭示了在适当的电压下，0阶、1阶和2阶衍射光束可以切换。实验得到一阶衍射的最大衍射效率为0.68；然而，它远远小于统一的理论极限。很可能，特殊光线和普通光线的光程长度之差不是线性分布的。
An electrically tunable liquid-crystal (LC) blazed grating was demonstrated by introducing a periodic pattern of pretilt angle that was controlled by adjusting the rubbing density. In the proposed LC grating, an asymmetrically varying LC molecular orientation was realized even without voltage application. The diffracted light intensity was controlled by adjusting the applied voltage, and the diffraction effect disappeared under a sufficiently high applied voltage. Asymmetric diffraction patterns were obtained and it was revealed that 0th-, 1st-, and 2nd-order diffraction beams can be switched with an appropriate applied voltage. A maximum diffraction efficiency of 0.68 for the 1st-order diffraction was experimentally obtained; however, it is much less than the theoretical limit of unity. It is likely that the difference between optical path lengths for extraordinary and ordinary rays is not linearly distributed.