Analytical Chiroptics of 2D and 3D Nanoantennas

The optical interaction of circularly polarized light with structurally chiral optical antennas results in chiral nanophotonics and antenna-enhanced chiral molecular sensing. Here we develop a simple analytical framework, connecting the far-field chiroptical transmission (circular dichroism) of feasible 2D and 3D nanoantennas with the electromagnetic polarizability of their elements. We report that the real and imaginary parts of the polarizability determine the line shape of the circular dichroism spectra, while the optical coupling of the comprising elements controls the spectral width and the absolute amplitude. On the example of the coupled-nanorods antennas, as a fundamental nanoplasmonic structure, we visualize the effect of the structural parameter variation on properly addressing and controlling the observed chiroptical effects.