Figure 1

A schematic illustration of the experiment to study optical manifestations of two-dimensional chirality in artificial planar structures. The inset shows a scanning electron micrograph of a typical chiral structure ($\mathrm{T}\mathrm{i}/\mathrm{A}\mathrm{u}/\mathrm{T}\mathrm{i}$ on silicon). Dark areas correspond to removed metallic film.Reuse & Permissions

Figure 2

(a) Polarization azimuth rotation (●, ○) and change in ellipticity (■, □) of light wave diffracted from left-handed (○, □) and right-handed (●, ■) gammadion arrays plotted as functions of the incidence angle. The two enantiomeric forms correspond to $\alpha =-45°$ (left handed) and $\alpha =+45°$ (right handed). Note the change of the sign of the polarization effects from left- to right-handed structures. For illustration and comparison purposes, theoretical results are presented which show polarization azimuth rotation (lines I and IV) and ellipticity (II and III) for a complementary design of gammadions made of an ideal conductor (I and III: left-handed gammadions; II and IV: right-handed gammadion). (b) Polarization azimuth rotation of light wave diffracted from left-handed (○, △, □) and right-handed (●, ▲, ■) gammadion arrays of different degrees of chirality plotted as functions of the angle of incidence. The different plots correspond to different internal angles $\alpha =-45°$ (○), $\alpha =-90°$ (△), $\alpha =-135°$ (□), $\alpha =+45°$ (●), $\alpha =+90°$ (▲), $\alpha =+135°$ (■). (c) Polarization azimuth rotation of light wave diffracted from left-handed (○) and right-handed (●) gammadion arrays and reflected from an unstructured $\mathrm{T}\mathrm{i}/\mathrm{A}\mathrm{u}/\mathrm{T}\mathrm{i}$ surface ($\times$) plotted as functions of the polarization azimuth of the incident wave. The lines $A$, $B$, and $C$ are the orientation mean values of the rotations for right- and left-handed gammadions and unstructured metal, respectively. Note that when the unstructured metal shows no polarization change [$\phi =0$ (180), 90°], left- and right-handed gammadion structures show opposite rotations, as indicated by the arrows. (d) Comparison of theoretical values of the continuous chirality measures calculated using the Zabrodsky and Avnir model (curve $A$), and using formula (1) (curve $B$), with experimentally observed values of azimuth rotation (solid connecting lines have been added by hand to distinguish between gammadions with different angles). In all cases normalized absolute values (magnitudes) are presented.Reuse & Permissions