Adiabatically encircling an exceptional point (EP) in a two-dimensional parameter space usually leads to the flip of instantaneous eigenstates. However, encircling dynamically the EP will arouse chiral modes transfer. The obtained eigenstate is determined by the encircling direction. The effect is robust against the size of the encircling loop in the parameter space once the EP is enclosed in the loop. It has been reported theoretically that the effect can also be observed when the loop does not enclose EP but keeps it at a proper distance. Here we experimentally validate the theoretical prediction by designing and fabricating a silicon-on-insulator based subwavelength grating waveguides structure. The chiral modes transfer is achieved via motivating and detecting the even and odd modes around the telecommunication wavelength. The results provide a more robust way for studying the topological properties of the non-Hermitian system.

中文翻译：

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用于手性模式转移的芯片实验，不包含特殊点

在二维参数空间中绝热地包围特殊点（EP）通常会导致瞬时本征态的翻转。但是，动态包围EP会引起手性模式转换。所获得的本征态由环绕方向确定。一旦将EP包含在循环中，该效果对于参数空间中环绕循环的大小将非常可靠。从理论上已经报道，当环路不包围EP而是将其保持在适当的距离时，也可以观察到这种效果。在这里，我们通过设计和制造基于绝缘体上硅的亚波长光栅波导结构，通过实验验证了理论预测。通过激发和检测电信波长附近的偶数和奇数模式，可以实现手性模式转移。