带有KTP缺陷的2维光子晶体设计与能带特性

Design and characteristics of two-dimensional photonic crystal with KTP defect

设计了一种通过改变缺陷介质折射率实现能带特性改变的可调谐2维光子晶体激光器微腔,在光子晶体中引入点缺陷磷酸氧钛钾(KTP),在KTP两端施加交流电场控制KTP晶体折射率变化。实验过程中观察到了正方排列的光子晶体随着KTP晶体折射率逐渐增大,晶体禁带数量减少,且向归一化频率小的方向移动,禁带宽度基本不变;而三角排列的晶格能带随着KTP折射率增大,禁带逐渐变窄,且有向低频方向移动的趋势。用平面波展开法分析了晶体的能带结构,得到理上的描述。

The plane wave expansion method is applied to simulate the band gap of a tunable two-dimensional photonic crystal micro cavity based on controlling the refractive index of defect medium.KTiOPO4（KTP） crystal is introduced to the planar photonic crystal as point defect,with its refractive index controlled by alternating current according to electro-optic effect.Numerical calculations and experimental results show that,with the refractive index of KTP increasing,the normalized frequencies of defect modes shift downward.The number of band gaps of the square lattice reduces,and the band gap of the triangle lattice narrows.