Dielectric inspired scaling of polarization conversion subwavelength resonances in open ultrathin chiral structures

It is shown that the scaling of subwavelength resonances in open ultrathin chiral structures can be obtained by varying only the permittivity of dielectric spacers, while multiband one-way polarization conversion and related asymmetric transmission remain possible. These features are quite general and obtainable in a wide range of parameter variation. Surprisingly, the difference in the power of ε for the classical ε-1/2 scaling rule and the empirical rules obtained in the present letter does not exceed 22%, giving an important entry point for future theoretical studies and design strategies. Both spectral scaling and conservation of the polarization characteristics can be achieved by using either tunneling or real-index impedance matching. The scaled structures with strong polarization and directional selectivity may have thickness of λ/100 and smaller. © 2015 AIP Publishing LLC.