Electrically Tunable Multicolored Filter Using Birefringent Plasmonic Resonators and Liquid Crystals

Dynamic tuning of color filters finds numerous applications including displays or image sensors. Plasmonic resonators are subwavelength nanostructures which can tailor the phase, polarization, and amplitude of the optical field, but they are limited in color vibrancy when used as filters. In this work, birefringence induced colors of plasmonic resonators and a fast switching thin liquid crystal cell are combined in a multicolored electrically tunable filter. With this mechanism, the color gamut of the plasmonic surface and the liquid crystal cell is mutually enhanced in order to generate all primary additive and subtractive colors with high saturation as well as different tones of white. A single filter is able to cover more than 70% of the color gamut of standard RGB filters by applying a voltage ranging between 2 and 6.5 V. This spectral selectivity is added in transmission without any loss in the image resolution. The presented approach is foreseen to be implemented in a variety of devices including miniature sensors or smart-phone cameras to enhance the color information, ultraflat multispectral imagers, wearable or head-worn displays, as well as high resolution display panels.