Gold helix photonic metamaterials: A numerical parameter study
J.K. Gansel, M. Wegener, S. Burger, and S. Linden
Opt. Express 18, 1059 (2010)
We have recently shown that metamaterials composed of three-dimensional
gold helices periodically arranged on a square lattice can be used as
compact “thin-film” circular polarizers with one octave bandwidth. The
physics of the motif of these artificial crystals is closely related to
that of microwave sub-wavelength helical antennas in end-fire geometry.
Here, we systematically study the dependence of the metamaterial’s
chiral optical properties on helix pitch, helix radius, two-dimensional
lattice constant, wire radius, number of helix pitches, and angle of
incidence. Our numerical calculations show that the optical properties
are governed by resonances of the individual helices, yet modified by
interaction effects. Furthermore, our study shows possibilities and
limitations regarding performance optimization.