Polarization-Controlled Transmissive Plasmonic Color Filter Using a Dimer-Aperture Array.

Complex color and polarization selective technologies are of increasing importance in scientific, security, and commercial imaging applications. A new dimeric plasmonic filter structure based on periodic aperture arrays is reported to provide an effective method for making planar color-selective structures by exploiting the properties of extraordinary optical transmission in thin metal films. The visible band transmission-mode polarization-dependent color filters reported in this work exploit only a single layer of aluminum patterned using a hexagonally periodic dimer-ellipse aperture structure. It is shown experimentally that the structure exhibits a minimum extinction ratio of over 20, 100, and 150 for red, green, and blue channels respectively, and a peak transmission of over 30%. It is demonstrated that dual images can be encoded using polarization selectivity into a single structure. The fidelity of the method is demonstrated with micro-scale reproductions of complex artworks showing the ability to reproduce 76% of the sRGB color gamut with polarization selectivity. The structure can be readily fabricated with only a single-step lithography and etching process, so that the technique may be widely used.