Multiring Slot Arrangements for Multiband Optical Activity of Bilayer Objects

Using the example of a waveguide metacell, it is shown that the introduction of additional rings of slots into a bilayer planar-chiral iris in a circular waveguide generates new resonances of the artificial optical activity (AOA). Their origin is the excitation of new eigenoscillations inside the bilayer gap and the corresponding rotation of the polarization plane at the output of the meta-object. Even with slight chirality of the layers, these rings increase the number of AOA resonances in the single-mode band. In loci of proximity and transformation of eigenoscillations inherent in planar-chiral bilayers, AOA maxima are observed with a rotation of the polarization plane up to 90°, and an expansion of the AOA band up to 10^% can be achieved.