电控液晶透镜的偏振转换和聚焦研究

Polarization conversion and focusing research ofelectrically controlled liquid crystal lens

【目的】针对径向偏振光束的产生和聚焦问题,提出了一种具有孔图案化电极的电控液晶偏振转换透镜。【方法】首先,装置采用扭曲径向液晶结构将线性偏振光旋转产生径向偏振光;然后,通过施加固定频率的驱动电压,使孔图案化电极和公共电极之间产生梯度电场,从而诱导液晶分子发生重定向;最后,在液晶层中形成具有梯度折射率的偏振转换透镜,将产生的径向偏振光进行聚焦。【结果】液晶偏振转换器产生了具有高度对称特性的径向偏振光,通过电控可以得到焦距约为116 mm,焦斑直径约为65.7μm的聚焦效果,实现了偏振转换和聚焦功能的集成化。【结论】本电控液晶偏振转换透镜结构简单,便于制作,光学性能稳定,为同时实现径向偏振光束的产生与聚焦提供了可靠的研究方案。

[Objective]An electrically controlled liquid crystal polarization conversion lens with hole patterned electrodes was proposed for the generation and focusing of radially polarized light beams.[Method]Firstly,the device used a twisted radial liquid crystal structure to rotate linearly polarized light to generate radially polarized light;then,a gradient electric field was generated between hole patterned electrodes and common electrodes by applying a fixed-frequency driving voltage to induce reorientation of liquid crystal molecules;finally,a polarization conversion lens with a gradient refractive index was formed in the liquid crystal layer to focus the generated radially polarized light.[Result]The liquid crystal polarization converter generates radially polarized light with highly symmetrical properties,which can be electrically controlled to achieve a focusing effect with a focal length of about 116 mm and a focal spot diameter of about 65.7μm,realizing the integration of polarization conversion and focusing function.[Conclusion]The electrically controlled liquid crystal polarization conversion lens boasts simple structure,convenience for fabrication,and stable optical performance,and provides a reliable research solution for simultaneous generation and focusing of radially polarized beams.