使用太赫兹时域光谱系统(THz-TDS)对基于超常光学透射现象的铝质亚波长圆孔阵列和牛眼结构进行了实验研究.实验中,使用包含00 1~2.7 THz的入射脉冲,观察到了明显的滤波效应,且滤波峰的中心频率恰好为两种结构所设计的0.53 THz.太赫兹波的高频部分,尤其是高于1 THz的部分发生了急剧地衰减.随着大样品中圆孔数量的增加,由于更加明显的周期性,滤波峰的中心漂移到0.26 THz.使用表面等离子体激元(SPPs)的相关理论以及运用有限元算法(FEM)对实验中观察到的超常光学透射现象和滤波效应进行模拟和分析,模拟的结果与实验数据吻合得非常好.
Terahertz (THz)filters based on extraordinary optical transmission from subwavelength hole array structure and bull's eye structure fabricated on aluminum slab is experimentally investigated by using THz time-domain spectroscopy (THz-TDS).The incident THz pulses with frequency from 0.1 to 2.7 THz could be observed to be filtered and the central peaks are both at 0.53 THz with designed parameters,respectively.The THz wave in high frequency could be observed to decrease dramatically,especially for the frequency above 1 THz.However,the transmission peak from the big sample with more holes shifts to low frequency at 0.26 THz due to the extension of periodical holes.Furthermore,finite element method (FEM) is employed to analyze this extraordinary optical transmission and filter phenomena with surface plasmon polaritons (SPPs) theory.The experimental results agree well with the simulation results.