Reflection-free one-way edge modes in a gyromagnetic photonic crystal
Reflection-free one-way edge modes in a gyromagnetic photonic crystal
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DOI：
10.1103/physrevlett.100.013905
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发表时间：
2008-01-11
影响因子：
8.6
通讯作者：
Soljacic, Marin
中科院分区：
文献类型：
--
作者：
Wang, Zheng;Chong, Y. D.;Soljacic, Marin
我们指出，类似于量子霍尔边缘态的电磁单向边缘模式，最初由Raghu和Haldane在具有狄拉克点衍生带隙的二维光子晶体中预测，可以出现在更一般的设置中。我们证明了旋磁光子晶体中的TM模式可以形式化地映射到周期性电磁场中的电子波函数，因此单向边缘模式存在的唯一条件是间隙以下所有频带的陈氏数不为零。在没有狄拉克点的微波频率下工作的方形晶格钇铁石榴石晶体中，时间反转破缺足够强，因此很容易观察到这种效应。对于实际的材料参数，边缘模式占据10%的带隙。结合该晶体的单向波导的数值模拟显示，通过强缺陷的透射率为100%。
We point out that electromagnetic one-way edge modes analogous to quantum Hall edge states, originally predicted by Raghu and Haldane in 2D photonic crystals possessing Dirac point-derived band gaps, can appear in more general settings. We show that the TM modes in a gyromagnetic photonic crystal can be formally mapped to electronic wave functions in a periodic electromagnetic field, so that the only requirement for the existence of one-way edge modes is that the Chern number for all bands below a gap is nonzero. In a square-lattice yttrium-iron-garnet crystal operating at microwave frequencies, which lacks Dirac points, time-reversal breaking is strong enough that the effect should be easily observable. For realistic material parameters, the edge modes occupy a 10% band gap. Numerical simulations of a one-way waveguide incorporating this crystal show 100% transmission across strong defects.