Feng Zhengyu, Ishikawa Ken
Opt Express. 2018 Nov 26;26(24):31976-31982. doi: 10.1364/OE.26.031976.
An optical phase grating prototype based on the homeotropic aligned antiferroelectric liquid crystal (AFLC) is demonstrated. By applying an in-plane electric field using comb-like electrodes, the helical structure of AFLC is deformed with the molecules rotating parallel to the electric field because of dielectric anisotropy. This deformation is called the pre-transitional effect of AFLC and induces biaxiality. By using this effect, a switchable phase grating is constructed using a 40μm thick cell filled with (S)-MHPOBC at 85°C. For 532nm TM polarized incident light, the maximum diffraction efficiency of 37.0% is achieved at the electric field of 1.8V/μm for the ± 1st order diffraction. The rise and decay times for the 1st order diffraction pattern are 510μs and 210μs, respectively. The high diffraction efficiency achieved under low field makes it promising for future electro-optical applications.
展示了一种基于垂直排列反铁电液晶（AFLC）的光学相位光栅原型。通过使用梳状电极施加面内电场，由于介电各向异性，AFLC的螺旋结构会发生变形，分子会平行于电场旋转。这种变形被称为AFLC的预过渡效应，并会诱导双轴性。利用这种效应，在85°C下使用一个填充有（S）-MHPOBC的40μm厚的液晶盒构建了一个可切换相位光栅。对于532nm TM偏振入射光，在±1级衍射的1.8V/μm电场下，实现了37.0%的最大衍射效率。1级衍射图案的上升和下降时间分别为510μs和210μs。在低电场下实现的高衍射效率使其在未来的电光应用中具有前景。
