How to improve the signal-to-noise ratio for circular polarizers consisting of helical metamaterials?

In this paper, we proposed new structured metamaterials with multi-helical nanowires to construct circular polarizers with higher S/N ratios. Compared with the single-helical ones reported by J. K. Gansel et al. [Science 325, 1513 (2009), Opt. Express 18, 1059 (2010)], which has a lower S/N ratio (~10 dB) due to the high intensity conversion, the circular polarizers with the multi-helical structures have average two orders higher S/N ratios (~35 dB). Simultaneously, other optical performances, such as operation bands, average extinction ratios, are also improved.