基于铌酸锂晶体的电控λ／2波片

利用有限元法分析了双面电板下铌酸锂晶体内部的电场分布。在规定匀强电场区域条件下，得到匀强电场区域大小随晶体宽度与电极宽度比值增大而增大的规律。在此基础上利用铌酸锂晶体的双横向普克尔效应设计了一种适用于任意光波长的电控λ／2波片。制作并测试了晶体宽度与电极宽度之比分别为2：1和3：1的电控铌酸锂λ／2波片，结果表明：这种波片可将一束线偏振的输入光转换成任意方向偏振的输出光，也可将任意偏振方向的输入光转换成固定方向偏振的输出光，并且晶体宽度与电极宽度比值越大，实验值与理论值符合得越好。

Voltage-Controlled Half-Wave Plate Based on LiNbO3 Crystal

The internal electric-field distribution of LiNbOa with double-sided electrodes is analyzed by the finite element method. The uniform electric field is defined, and its size increases with the ratio between crystal width and electrode width increasing. A voltage-controlled half-wave plate which is applied to any wavelength is proposed based on the dual-transversal Pockels effect in LiNbOa. Two half-wave plates are designed and tested, that the ratio is 2 ： 1 and 3 = 1 between crystal width and electrode width respectively. Experimental results show that the polarization direction of a light can be trans-formed into arbitrary polarization direction, vice versa, and the ratio is bigger, the experimental value is better coincident with theoretical value.