High-transmission rotation-angle-dependent plasmonic color filter

Conventional color filters usually have low transmittance, or only one fixed output color. In this paper, we present a simple and effective approach to achieve color filtering with a high-transmission rotation-angle-dependent plasmonic structure, which comprises surface arrays of "bowknot” (a pair of isosceles triangles) nano-aperture structure in an ultrathin silver film. The influence of the rotation angle and polarization angle of the aperture structure on the performance of the filter is studied, and a structure rotation angle dependent filter design strategy is proposed. It is found that the aperture structure rotation angle can greatly improve the performance of the color filter (up to 70% transmission), and it is possible to filter a variety of colors only by changing the aperture structure rotation angle, which may enable a wide variety of potential applications.