We theoretically present a simple nanophotonics platform, where the photonic corner states can be obtained in high frequencies. For the breathing Kagome lattice with three bearded truncations, we show that a pair of bonding and anti-bonding corner states can be observed in the gapped bulk bands, even for a topologically trivial lattice. In particular, this anti-bonding corner state is totally embedded in the bulk modes for topologically non-trivial structures, forming a bound state in continuum. We further verify that these corner states are protected by the symmetry and can be excited by merely one point source, even in a loss system. The newly found corner modes may expand our understanding of the high-order corner modes in a more general framework, involving both topology and symmetry.

中文翻译：

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截断对Kagome晶格中光子角状态的影响

从理论上讲，我们提供了一个简单的纳米光子学平台，可以在其中以高频率获得光子角状态。对于具有三个胡须截断的呼吸Kagome晶格，我们表明即使在拓扑琐碎的晶格中，也可以在有空隙的体带中观察到一对键合和反键角状态。尤其是，此抗粘结角状态完全嵌入到拓扑非平凡结构的体模式中，从而形成连续体的束缚状态。我们进一步验证了这些角状态受到对称性的保护，即使在损耗系统中也只能由一个点源激发。新发现的拐角模式可以在更一般的框架中扩展我们对高阶拐角模式的理解，涉及拓扑和对称性。