Sun Kaili, Cai Yangjian, Levy Uriel, Han Zhanghua
Shandong Provincial Key Laboratory of Optics and Photonic Devices, Center of Light Manipulation and Applications, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
Department of Applied Physics, The Hebrew University of Jerusalem, Jerusalem, Israel.
Beilstein J Nanotechnol. 2023 Mar 6;14:322-328. doi: 10.3762/bjnano.14.27. eCollection 2023.
We elucidate that guided modes supported by a regular photonic crystal slab structure composed of a square lattice of air holes in a silicon slab will transition into quasi-guided (leaky) modes when the radius of every second column of air holes is changed slightly. This intentional geometric perturbation will lead to a doubling of the period in one direction and the corresponding shrinkage of the first Brillouin zone. Because of the translational symmetry in the -space, leaky waves inheriting the spatial dispersion of the original guided modes, which do not interact with external radiation, will appear with the dispersion curves above the light cone. Our results show that ultrahigh Q-factor resonances with large operating bandwidth can be achieved. Interestingly, the perturbation in only one direction of the photonic lattice will lead to an in-plane wave number-dependent resonance characteristic in both directions. Our numerical results demonstrate a local enhancement of the electric field magnitude by the order of 10, which is even more significant than those in most plasmonic structures. These quasi-guided modes with superior properties will provide a new platform for efficient light-matter interactions.
我们阐明，当硅平板中由气孔正方形晶格组成的规则光子晶体平板结构所支持的导模，在每隔一列气孔的半径略有变化时，将转变为准导模（泄漏模）。这种有意的几何微扰将导致在一个方向上周期加倍，以及第一布里渊区相应收缩。由于在-空间中的平移对称性，继承了原始导模空间色散且不与外部辐射相互作用的泄漏波，将出现在光锥上方的色散曲线上。我们的结果表明，可以实现具有大工作带宽的超高品质因数共振。有趣的是，仅在光子晶格的一个方向上的微扰将导致在两个方向上与面内波数相关的共振特性。我们的数值结果表明电场强度局部增强了10倍，这甚至比大多数等离子体结构中的增强更为显著。这些具有优异特性的准导模将为高效的光与物质相互作用提供一个新平台。
