Multi-mode circular dichroism in n-fold rotational symmetric metamaterials

In this article, the effects of the rotation angle between upper and lower n-fold rotational symmetric nano-structures are studied. Various modes of circular dichroism (single wavelength band, dual-wavelength bands, and more than two wavelength bands) in the wavelength band from 3.3 to 5 mu m are realized. Circular dichroism up to 0.798 are observed. Meanwhile, sensitivity of circular dichroism to the rotation angle and reconfigure strategy for opposite responses has been discussed. Based on Born-Kuhn model, physical mechanism of mode's switching is explained with charge distributions. The multi-mode chiroptical responses in mid-infrared band and the variety of design strategies have potential applications in the field of tunable multi-band chiral devices.

Automated summary

This article investigates the effects of the rotation angle between upper and lower n-fold rotational symmetric nano-structures. Various modes of circular dichroism in the wavelength band from 3.3 to 5 mu m are achieved. The sensitivity of circular dichroism to the rotation angle and the reconfigure strategy for opposite responses are discussed. The physical mechanism of mode's switching is explained using the Born-Kuhn model.