液晶对双通道光子晶体滤波器的调制

Modulation of Liquid Crystal on Two- Channel Photonic Crystal Filters

利用向列相液晶材料的热光效应,引入光子晶体缺陷中,构造双通道光子晶体滤波器模型PC|LC|A|LC|PC,并研究液晶材料温度对双通道滤波器的调制作用。结果表明,当引入液晶单缺陷时,禁带中出现一条窄带缺陷模,其透射率约为20.7%;当引入液晶双缺陷时,禁带中出现两条窄带缺陷模,两条缺陷模的透射率最高分别达到99.4%和99.6%,可实现双通道滤波功能;在不超过液晶相的临界温度范围内,滤波器的滤波通道位置随着液晶材料温度的增大向短波方向移动,左则通道的滤波带宽略有变宽的趋势,但右侧通道的滤波带宽几乎不受温度变化的影响。研究结果为频率可调的双通道光子晶体滤波器的实际设计提供理论指导意义。

The two- channel photonic crystal filter models of PC ｜ LC ｜ A｜ LC ｜ PC are constructed by introducing the thermo- optic effect of the nematic liquid crystal materials into the photonic crystal defect. The modulating action of liquid crystal materials＇ temperature on the two- channel filters is studied too. The results show that when there is only one of defect of liquid in the photonic crystal,the one defect mode with a transmission rate of 20. 7%appears in the forbidden band. When the double defects of liquid crystal are introduced,two narrow band defect modes appear in the band gap,and the highest transmittances of each defect mode are 99. 4% and 99. 6%,respectively. It can realize the dual channel filter functions. In the critical temperature range of the liquid crystal phase,with the increasing of the temperature of liquid crystal material,the channel position of the filter moves to the short wave direction,and the filter band- width of left channel has a tendency to widen,but the other one channel in the left is almost not affected by temperature changes. The result can provide theoretical guidance for the practical design of a dual channel photonic crystal filter.