Switchable Plasmonic Holograms Utilizing the Electro-Optic Effect of a Liquid-Crystal Circular Polarizer

A concept for switchable holograms with high diffraction efficiency based on geometrical metasurfaces is proposed. The phase hologram studied is composed of plasmonic nanoantennae with varying orientations. Its diffraction pattern is known to depend on the state of polarization of the incident radiation. Maximum brightness of the reproduced holographic images is obtained by circularly polarized radiation, while the position of the respective image depends on the handedness of this circularly polarized radiation. For the purpose of switching, the hologram is illuminated through an electrically addressable liquid-crystal filter, which transforms linear polarization to either right circular or left circular polarization, depending on the applied voltage. First experimental results indicate reasonable switching when a twisted nematic active layer and a uniform nematic passive layer are combined in a compact polarization converter.