负折射激活介质一维光子晶体超窄带滤波器研究

把一维时域有限差分方法用于可见光区一维光子晶体超窄带滤波设计研究,首先适当选择完整的一维二元光子晶体参数找到可见光区中的禁带,然后在完整一维光子晶体中间引入缺陷层可得到在某一波长出现超窄通带.进一步研究缺陷层参数物理厚度、折射率对超窄带的位置、透过率的调节,数值结果表明当缺陷层用无损介质时超窄通带的中心波长与缺陷层物理厚度、折射率有很大关系,透过率与它们关系不大.当介质是有损或激活介质时超窄通带的中心波长与介质折射率虚部消光系数、激活系数大小无关,消光系数越大透过率越小,激活系数与透过率没有线性关系但有最大值出现,当缺陷层介质是负折射材料时折射率数值在一定范围内取值同样会出现窄带滤波特性,折射率数值绝对值较大时在可见光区禁带中会出现多个透过峰.

Design of Supernarrow Band-pass Filter of One-dimensional Photonic Crystal in Negative Refractive Activity Medium

Finite-difference time-domain method (FDTD) is used in the study and design of supernarrow band-pass filter of one-dimensional photonic crystal in the range of visible light. Firstly,the band gap of perfect 1-D dual photonic crystal in the range of visible light are found by choice suitable parameter. Then,supernarrow band pass in special wavelength are obtained by introducing defect layer in perfect one-dimensional photonic crystal. Further investigations are carried in the adjusting of position and transmission coefficient of supernarrow band-pass with the physics thickness and refractive index of defect layer. The results indicate that the position of center wavelength of supernarrow band-pass have relation with physics thickness and refractive index of defect layer when the defect layer are nonloss material. The transmission coefficient is independent. The position of center wavelength of supernarrow band-pass has no relation with the extinction coefficient and activation coefficient when the defect layers are nonloss or activation material. When the extinction coefficient is higher,the transmission coefficient is lower. The activation coefficient has no linear relation with transmission coefficient but have a max value when the transmission coefficient changed. The characteristic of narrow band pass also occurred when the defect layers are negative material. There are many transmission peaks in band gap of visible light range when the refractive index is high.