论文标题
开放的无损周期性波导中的复杂模式
Complex modes in an open lossless periodic waveguide
论文作者
论文摘要
开放周期性波导的指导模式，在主要传播方向上具有周期性，是围绕波导芯的Bloch模式，横向横向方向没有辐射损失。某些引导模式可以具有复杂的传播常数，即即使周期性波导无损（无吸收损失），也可以具有复杂的Bloch波数。这些所谓的复杂模式是物理解决方案，每当波导具有不连续性和缺陷时，就可以激发入射波。我们表明，开放的介电周期性波导形式带中的复杂模式，并且频带的端点可以分类为少数情况，包括常规引导模式的分散曲线，连续性，退化复合模式和特殊衍射溶液的限制状态的极端曲线。我们的研究为定期波导提供了改进的理论理解，并为其实际应用提供了有用的指导。
Guided modes of an open periodic waveguide, with a periodicity in the main propagation direction, are Bloch modes confined around the waveguide core with no radiation loss in the transverse directions. Some guided modes can have a complex propagation constant, i.e. a complex Bloch wavenumber, even when the periodic waveguide is lossless (no absorption loss). These so-called complex modes are physical solutions that can be excited by incident waves whenever the waveguide has discontinuities and defects. We show that the complex modes in an open dielectric periodic waveguide form bands, and the endpoints of the bands can be classified to a small number of cases, including extrema on dispersion curves of the regular guided modes, bound states in the continuum, degenerate complex modes, and special diffraction solutions with blazing properties. Our study provides an improved theoretical understanding on periodic waveguides and a useful guidance to their practical applications.
