论文标题
波浪形光栅：宽带反射器和Fabry-Perot BIC
Wavy optical grating: wideband reflector and Fabry-Perot BICs
论文作者
论文摘要
在这项研究中，我们从理论上和数字上研究了通过应用光谱元件方法，由波浪介电板组成的光栅的谐振模式和反射率。波浪形的存在将波导模式转化为泄漏的谐振模式。一些具有特定纵向波数的共振模式具有无限的Q因子，而其他共振模式具有有限的Q因子。对于具有零纵向波数的泄漏谐振模式，Q因子与波浪形的幅度成反比。一系列多个低Q波波式光栅在很大的带宽中具有很高的反射率。双层波浪形光栅形成一个Fabry-Perot腔，该腔位于谐振频率下的连续体（BICS）中的Fabry-Perot结合状态。 Fabry-Perot腔的Q因子可以通过调节两个波浪板之间的距离来调节。波浪形的形状可以通过平坦的电介质平板中的振动波产生，以便可以按需控制BICS模式和宽带反射率。
In this study, we theoretically and numerically investigate the resonant modes and reflectance of an optical grating consisting of a wavy dielectric slab by applying the spectral element method. The presence of the wavy shape transforms the waveguide modes into leaky resonant modes. A few resonant modes with specific longitudinal wave number have infinitely large Q factor, while the other resonant modes have finite Q factor. For the leaky resonant mode with zero longitudinal wave number, the Q factor is inversely proportional to the amplitude of the wavy shape. An array of multiple low-Q wavy gratings has a high reflectance in a large bandwidth. A double-layer wavy grating forms a Fabry-Perot cavity, which hosts Fabry-Perot bound states in the continuum (BICs) at the resonant frequency. The Q-factor of the Fabry-Perot cavity can be tuned by adjusting the distance between the two wavy slabs. The wavy shape could be generated by a vibrational wave in a flat dielectric slab so that the BICs mode and wideband reflectance could be controlled on-demand.
