Centre for Optical and Electromagnetic Research, State Key Laboratory for Modern Optical Instrumentation, Zhejiang University, Hangzhou 310058, China.
Opt Lett. 2012 Oct 1;37(19):4110-2. doi: 10.1364/OL.37.004110.
We demonstrate that one-way electromagnetic modes could be sustained by the edge of a gyromagnetic photonic crystal slab of triangular lattice under an external dc magnetic field. The applied magnetic field breaks the time-reversal symmetry of the three-dimensional system, and thus the original degeneracy point in k space, at which two dispersion surfaces intersect, is lifted, resulting in a photonic band gap below the light cone. At this band gap, the one-way mode is localized horizontally to the slab edge, while confined by the index contrast in the vertical direction.
我们证明了在外部直流磁场作用下，各向异性的电磁模式可以在三角晶格的亚铁磁共振光子晶体的边缘被维持。外加磁场打破了三维系统的时间反演对称性，从而使原来在 k 空间中两个色散面相交的简并点被消除，在光锥之下产生了光子带隙。在这个带隙中，单向模式在水平方向上被限制在晶体边缘，同时在垂直方向上被折射率对比所限制。
