复介电常量双缺陷层的镜像对称光子晶体特性

Properties of Mirror Symmetrical Photonic Crystals of Dielectric Constant Defect Layer with Imaginary Part

利用传输矩阵法研究了两个复介电常量缺陷层镜像对称一维光子晶体的带隙结构和光传输特性。重点讨论了缺陷层的复介电常量的虚部为负值且光学厚度为λ0/4的情形时对传输特性的影响。研究发现:当在光子晶体的两端加入具有负虚部的复介电常量缺陷层后,多处出现了较强的透射峰增益。随着缺陷层复介电常量的虚部与实部比值的增加,各处透射峰增益变化规律不同。但中心波长处的缺陷膜的位置和高度不变。这为光子晶体同时实现多通道超窄带滤波器和不同放大倍数的光放大微器件的设计提供了理论基础。而在光子晶体的两端加入具有正虚部的复介电常量缺陷层后,各透射峰都出现了吸收现象,且随着其正虚部值I的增加,吸收越明显,这给光子晶体实现放大功能提供了理论指导。

By using the optical tranfer matrix method, the band function and the optical transmission properties of mirror symmetrical photonic crystals of two dielectric constant defect layer with imaginary part are studied, especially discussing on the case of negation imaginary part and the optical thickness of the defect layer is λο/4. The investigation results show that several large transmittance gains appear at the transmittance bands if the dielectric constant defects with negative imaginary part are added in the photonic crystals. With the increasing of the ratio of imaginary and real part of defect＇s dielectric constant, the transmittance gains will change with different rule, but the transmissivity of the defect film at middle wavelength is invariable. The conclusion might be used to multiple channel narrow band filter and multiple channel optical amplification device with different amplificatory multiple synchronously. However, all of the transmittance peaks are minished if the imaginary part of the defect layer＇s dielectric constant was positive, because the transmittance peaks are absorbed in this case. With the increasing of the imaginary, the transmittance is reducing. The conclusion leads to use photonic crystals for optical amplification device theoretically.