Enhanced Volume Optical Chirality in Electromagnetically Balanced Plasmonic Helices

We numerically investigate optical chirality generation within the interior volume of plasmonic gold helices operating in the mid‐infrared spectral range. Rather than relying on polarization or handedness switching, our approach uses geometric tuning of the helix height to achieve electromagnetic balance between the induced electric and magnetic dipole moments. By comparing single‐turn and bifilar helices, we show that electromagnetically balanced geometries generate enhanced volume‐averaged optical chiral density with comparable magnitude and sign for selected linear and circular polarization excitations. The bifilar helix provides an optical chirality enhancement approximately one order of magnitude larger than that of the single‐turn helix due to stronger electric–magnetic dipolar coupling and increased field confinement. We further demonstrate that increasing the bifilar helix height modifies the dipole balance and can reverse the sign of the optical chirality without changing the structural handedness. These results establish electromagnetically balanced plasmonic helices as a geometry‐controlled platform for enhanced chiral near‐field generation in the mid‐infrared.