含负折射率缺陷的一维光子晶体的杂质带

利用传输矩阵方法研究了含负折射率缺陷的一维光子晶体的透射谱.以19个周期的1/4波堆存在3个负折射率缺陷的光子晶体为例进行了数值计算.结果表明:如果改变缺陷的折射率,缺陷模之间的耦合作用将发生改变,带隙中形成的杂质带也随之改变;当这个折射率取适当值时,在禁带中出现多个尖锐的透射峰,与正折射率缺陷构成的杂质带不同.

含有负折射率缺陷的光子晶体中的缺陷模的紧束缚法

采用紧束缚法,研究了含有多个负折射率缺陷的光子晶体中的缺陷模,导出了缺陷模频率方程。然后数值计算了含有三个负折射率缺陷的一维光子晶体的透射谱。结果表明:光子带隙中缺陷模将出现分裂,分裂后缺陷模的数目与半波缺陷数目相同,而缺陷模的间隔随着半波缺陷间隔层数的增加而减小,缺陷模间隔的大小有微小的不对称,最后形成一个缺陷模通带。

含色散负折射率缺陷一维Sinc函数型光子晶体的光学传输特性

应用传输矩阵法对含色散负折射率缺陷一维sinc函数型光子晶体的光学传输特性进行了研究。结果表明:含色散负折射率缺陷的sinc函数型光子晶体比含同样缺陷的余弦函数型光子晶体具有更宽阔的光子禁带;该光子晶体的禁带宽度随着介质层折射率nB(0)、nA(0)或半周期厚度的增大迅速收缩变窄,缺陷模消失;当光波入射角增大时,禁带宽度变宽,缺陷模与禁带一起红移;计算还发现该禁带结构对色散负折射率缺陷层的位置变动十分敏感;但是,缺陷层厚度的变化不会改变禁带的位置和宽度,此时缺陷模会随着缺陷层厚度的增大向着禁带中心移动。这些结论对一维函数型光子晶体的设计具有重要参考意义。

Properties of Defect Modes in Periodic Lossy Multilayer with Negative-Index-Materials

Employing the characteristic matrix method, this study investigates transmission properties of onedimensional defective lossy photonic crystals composed of negative and positive refractive index layers with one lossless defect layer at the center of the crystal. The results of the study show that as the refractive index and thickness of the defect layer increase, the frequency of the defect mode decreases. In addition, the study shows that the frequency of the defect mode is sensitive to the incidence angle, polarization, and physical properties of the defect layer, but it is insensitive to the small lattice loss factor. The peak of the defect mode is very sensitive to the loss factor, incidence angle, polarization, refractive index, and thickness of the defect layer. This study also shows that the peak and the width of the defect mode are affected by the numbers of the lattice period and the loss factor. The results can lead to designing new types of narrow filter structures and other optical devices.