Li Liangsheng, Li Yunzhou, Zhu Yong, Yin Hongcheng
Science and Technology on Electromagnetic Scattering Laboratory, Beijing, 100854, China.
Kunming Shipbuilding Equipment Research and Test Center, Kunming, 650051, China.
Sci Rep. 2020 Oct 26;10(1):18243. doi: 10.1038/s41598-020-75308-x.
The bound states in the continuum (BICs) have been investigated by simulating the optical reflectivity of a tri-layer photonic crystal slab. We found that optical BICs can occur in a class of photonic crystal systems with [Formula: see text], [Formula: see text] or [Formula: see text] rotational symmetries, which are constructed by three identical photonic crystal slabs. By applying the two mode coupled model, we obtain the reflectivity formula to fit the numerical data and evaluate the lifetime of radiation decay. In vicinity of BIC, the lifetime diverges as a power law form, when approaching the BIC point. The infinity life time of [Formula: see text] in the tri-layer structure indicate that it is a true BIC. The [Formula: see text] occurs robustly in tri-layer structures, but the resonance frequency of the BICs is dependent on the permittivity of slab, air-hole size and hole shape.
通过模拟三层光子晶体平板的光学反射率，对连续统中的束缚态（BICs）进行了研究。我们发现，光学BICs可以出现在一类具有[公式：见正文]、[公式：见正文]或[公式：见正文]旋转对称性的光子晶体系统中，这些系统由三个相同的光子晶体平板构成。通过应用双模耦合模型，我们得到了反射率公式以拟合数值数据，并评估辐射衰减的寿命。在BIC附近，当接近BIC点时，寿命以幂律形式发散。三层结构中[公式：见正文]的无限寿命表明它是一个真正的BIC。[公式：见正文]在三层结构中稳健出现，但BICs的共振频率取决于平板的介电常数、气孔尺寸和孔形状。
