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

Abstract

In this article, the effects of the rotation angle between upper and lower n-fold rotational symmetric nanostructures 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 µm are realized.Absorption up to 0.994 and absorptive circular dichroism up to 0.867 are observed. Meanwhile, sensitivity of circular dichroism to the rotation angle and recon gure 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 eld of thermal remote sensing detection and tunable multiband chiral devices.