论文标题
通过向前和向后传播波混合而引起的间接带隙的脱落性特殊点
Exceptional Points of Degeneracy with Indirect Bandgap Induced By Mixing Forward and Backward Propagating Waves
论文作者
论文摘要
我们证明，在两个耦合的波导中获得了异常的变性点（EPD），而无需诉诸增益和损失。我们展示了一个一般概念，即前向和后退波的适当耦合产生的模式显示了二的EPDS，并且组速度消失了。我们通过使用耦合模式理论以及通过在介电板中与光栅耦合的光的全波数值模拟来验证我们的见解，而当一个人支撑向前波时，而另一个（光栅）支持向后波。我们还演示了如何在指导系统中支持向后和向前波的引导系统中实现光子间接带隙，显示其与EPD的发生的关系并提供设计程序。
We demonstrate that exceptional points of degeneracy (EPDs) are obtained in two coupled waveguides without resorting to gain and loss. We show the general concept that modes resulting from a proper coupling of forward and backward waves exhibit EPDs of order two and that there the group velocity vanishes. We verify our insight by using coupled mode theory and also by fullwave numerical simulations of light in a dielectric slab coupled to a grating, when one supports a forward wave whereas the other (the grating) supports a backward wave. We also demonstrate how to realize photonic indirect bandgaps in guiding systems supporting a backward and a forward wave, show its relations to the occurrence of EPDs, and offer a design procedure.
