Imaging performance of the liquid-crystal-adaptive lens with conductive ladder meshing
Imaging performance of the liquid-crystal-adaptive lens with conductive ladder meshing
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DOI：
10.1364/ao.36.008958
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发表时间：
1997-12-01
期刊：
影响因子：
1.9
通讯作者：
Kowel, ST
中科院分区：
文献类型：
--
作者：
Chan, WW;Kowel, ST
液晶自适应透镜（LCAL）是一种利用渐变折射率使光线聚焦的电光器件。一组电极控制液晶薄膜中的折射率变化。通过改变施加在该器件上的电压，可以改变液晶自适应透镜的焦距。电极的离散性会导致相位像差。我们引入了一种新颖的电极结构，称为导电梯形网格（CLM），我们开发这种结构是为了大幅降低静态相位像差（由电极结构引起）。为了降低动态相位像差（与不准确的电压有关），我们使用了一种模拟退火电压抖动技术。推导出了液晶自适应透镜的相干传递函数，以便从理论上预测CLM液晶自适应透镜的性能。理论分析表明，与之前版本中65%的散射相比，CLM液晶自适应透镜对入射光的散射小于30%。在相干照明下，针对平面波照明测量了球形液晶自适应透镜的焦斑性能。由于球形液晶自适应透镜质量的提高，在白光照明下，针对单一入射偏振进行了真实的成像实验。就分辨率而言，球形液晶自适应透镜所成的像与固定透镜所成的像相当，尽管对比度较差。（C）1997年美国光学学会
The Liquid-crystal-adaptive lens (LCAL) is an electro-optical device that utilizes a graded index of refraction to bring light to focus. A set of electrodes controls the index variation in a liquid-crystal thin film. One can vary the focal length of the LCAL by changing the voltages applied to the device. The discrete nature of the electrodes causes phase aberrations. We introduce a novel electrode architecture, called conductive ladder meshing (CLM), that we developed to greatly reduce the static phase aberration (caused by the electrode structure). To reduce the dynamic phase aberration (associated with inaccurate voltages), we used a simulated-annealing voltage-dithering technique. The coherent transfer function of the LCAL was derived so that the performance of the CLM LCAL could be predicted theoretically. Theoretical analysis indicates that the CLM LCAL scatters less than 30% of incident light compared with scattering of 65% in the previous version. The focal-spot performance of the spherical LCAL was measured under coherent illumination for plane-wave illumination. Because of the improved quality of the spherical LCAL, true imaging experiments are demonstrated for a single incoming polarization under white-light illumination. Images formed by the spherical LCAL are comparable with those formed by a fixed lens in terms of resolution, although the contrast is worse. (C) 1997 Optical Society of America.