No abstract

Nature provides impressive examples of chiral photonic crystals, with the notable example of the cubic so-called srs network (the label for the chiral degree-three network modeled on SrSi2) or gyroid structure realized in wing scales of several butterfly species. By a circular polarization analysis of the band structure of such networks, we demonstrate strong circular dichroism effects: The butterfly srs microstructure, of cubic I4(1)32 symmetry, shows significant circular dichroism for blue to ultraviolet light, that warrants a search for biological receptors sensitive to circular polarization. A derived synthetic structure based on four like-handed silicon srs nets exhibits a large circular polarization stop band of a width exceeding 30%. These findings offer design principles for chiral photonic devices.

No abstract

readily observed in nature, e.g., artificial magnetism, [1] negative refractive index, [2][3][4] epsilon-and-mu-near-zero, [5] light trapping, [6] or low frequency plasmons. [7] Such properties make metamaterials a promising platform to design devices with a wide range of uses for society including super-resolution imaging, [8][9][10] invisibility cloaking, [11][12][13] chemical/ biomolecular sensing, [14][15][16] antennas, [17] or absorbers. [18,19] These new functionalities can be achieved by for example using building blocks (so-called meta-atoms) arranged at length scales that are much smaller than the incident wavelength. [20][21][22] In this review article, we focus on the engineering of the optical properties for metamaterials active in the visible and near-infrared (IR) wavelength range. Structural features should be on length scales significantly smaller than the visible wavelengths (400-750 nm) to avoid