为了研究关于复介电常量缺陷层镜像对称的1维光子晶体的带隙结构和光传输特性，利用传输矩阵法，讨论了缺陷层的复介电常量的虚部为负值且光学厚度为λ₀／2的情形对传输特性的影响。结果表明，当在光子晶体加入复介电常量的缺陷层后，在靠近光子带隙边缘，出现了较强的透射峰增益；随着缺陷层复介电常量的实部和虚部的增加，透射增益先增加后减少，中间存在一极值点，但缺陷膜的位置和高度不受复介电常量的实部和虚部的影响。这一结果为光子晶体同时实现超窄带滤波器和光放大微器件提供了理论基础。

By means of optical transfer maxtrix,the band function and the optical transmission properties of mirror symmetrical photonic crystals with an imaginary part of dielectric constant defect were studied,especially in the case of negation imaginary part and the λ₀/2 optical thickness of the defect. The investigation results show that a large transmittance gain appears at the photonic band edges if an imaginary part of dielectric constant defect is added in the photonic crystals. With the increasing of the imaginary and the real part of defect's dielectric constant,the transmittance gain is increasing firstly then decreasing and in the middle the transmittance gain apex appears. However,the place and altitude of the defect film are invariable. The conclusion is useful for narrow band filter and optical amplification device synchronously.