We introduce a topological theory of perfect isolation: perfect transmission from one side and total reflection from the other side simultaneously. The theory provides an efficient approach for determining whether such a perfect-isolation point exists within a finite parameter space. Herein, we demonstrate the theory using an example of a Lorentz nonreciprocal metasurface composed of dimer unit cells. Our theory also suggests that perfect-isolation points can annihilate each other through the coalescence of opposite topological charges. Our findings could lead to novel designs for high-performance optical isolators.

中文翻译：

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完美的超表面隔离器的拓扑理论

我们介绍了一种完全隔离的拓扑理论：从一侧的完美透射和从另一侧的全反射。该理论为确定这样的理想隔离点是否存在于有限参数空间内提供了一种有效的方法。在这里，我们使用由二聚体晶胞组成的Lorentz不可逆超颖表面的示例来证明该理论。我们的理论还表明，理想隔离点可以通过相反拓扑电荷的合并而相互抵消。我们的发现可能会导致高性能光学隔离器的新颖设计。