电光晶体用于快速变焦的设计

Design of electro-optic crystals applied in fast zooming scheme

在利用晶体的电光效应实现快速变焦时,需要合理地设计电光晶体及电极结构。基于晶体电光效应的基本原理,提出了其设计的基本原则和思路,并通过对一次电光晶体(铌酸锂晶体)和二次电光晶体(钽铌酸钾晶体)内部非均匀电场及其总附加光程的模拟和比较,获得了优化的电光晶体及电极设计结果。在此基础上,开展了电光晶体用于快速变焦设计的性能分析,并讨论了电光晶体长度、外加电压等参数对总附加光程的影响。结果表明:电光晶体的附加光程调制的曲率半径随控制电压增大而减小,在加载电压不变的情况下随晶体厚度的增大而增大。因此,在实际应用中,需要对晶体厚度和加载电压综合进行考虑,以获得最佳的变焦效果。

To achieve fast zooming by using electro-optic（EO） crystal, the EO crystal and electrode structures are required to be designed properly. Based on electro-optic effect, the basic principle and way of the EO crystal design were proposed. By means of simulation and comparison of internal non-uniform electric field and total additional optical path between linear EO crystal（lithium niobate crystal） and square EO crystal（tantalum potassium niobate crystal）, the optimization of the EO crystal and electrode design were obtained. On this basis, the performance of the EO crystals for fast zooming was simulated and analyzed. The influence of the applied voltage and crystal thickness on the total additional optical path was discussed. Results show that the curvature radius of additional optical path decreases with the increasing of the control voltage, while increases with the increasing of the crystal thickness for a given applied voltage. In practical applications, the crystal thickness and applied voltage need to be considered comprehensively to achieve better zooming effect.