Comparative study of metallic and dielectric helix photonic metamaterial

We compare the performance of metallic and dielectric thin film helix photonic metamaterial numerically. The simulated metal helix provides a 4 μm broad band circular dichroism with a polarization suppression ratio of 20:1. The transmission efficiency of the metal helix drops significantly with increasing number of helix turns and angle of incidence. Contraire, the simulated silicon dielectric helix structure provides an extremely high polarization suppression ratio above 2,300:1 with almost 100% transmission over a wide range of incident angles. The results provided highlights the trade-offs between the transmission efficiency and the specular and angular bandwidth for designing practical thin-film circular polarizers.