The ability of three-dimensional chiral molecules to rotate the polarization state of light (a gyrotropy) is one of the most fundamental phenomena of electrodynamics. It was discovered by F. Aragot in 1811. Helical arrangements are classic examples of gyrotropic chiral molecules. The concept of chirality also exists in two dimensions where a planar object is said to be 2D-chiral if it cannot be superimposed on its mirror image unless it is lifted from the plane. An Archimedes Spiral is an example of such an object. Arnaut and Davis [1, 2] and Hetch and Barron [3] are the pioneers introduced planar chiral structures in electromagnetic researches. Two-dimensional chirality does not lead to electromagnetic effects such as gyrotropy in the same way as conventional 3D chirality and recently became a subject of intense investigation started in [4]. It is not only because of its fundamental importance and new polarization effects possible with planar chiral media, but also because of the practical opportunities they present for the creation of compact optical components that can manipulate the polarization state of light and microwave radiation in the near and far fields. The composite planar chiral materials are artificially engineered structures (planar metamaterials). In order to the chiral properties of these artificial planar materials to be designed more efficiently, quantifiable measures of 2D chirality can be introduced in number of ways [5-7].
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