We examine the Kramers–Kronig relations between the circular dichroism and the optical rotation dispersion in the k-space obtained from a chiral metasurface with a reduced rotational symmetry. We operate a leakage-radiation microscopy system to probe the near-field plasmonic modes and measure the polarization effects of the grating. By using our system we were able to capture and analyze the plasmonic modes at both air/gold and gold/glass interfaces. The k-space mapping of the chirality parameters allows us to fully analyze the optical activity of the metasurface. We experimentally find that the reduction in rotational symmetry affects the locality condition which unavoidably leads to the deviation from the Kramers–Kronig relation.

我们研究了从具有降低的旋转对称性的手性形表面获得的k-空间中圆二色性和旋光色散之间的Kramers-Kronig关系。我们使用泄漏辐射显微镜系统来探测近场等离子体模式并测量光栅的偏振效应。通过使用我们的系统，我们能够捕获和分析空气/金和金/玻璃界面的等离子体模式。手性参数的k空间映射使我们能够全面分析超表面的光学活性。我们通过实验发现，旋转对称性的降低会影响局部条件，这不可避免地导致偏离Kramers-Kronig关系。