Electrically induced red, green, and blue scattering in chiral-nematic thin films.

Cholesteric liquid-crystalline materials are abundant in nature such as condensed phases of DNA, plant cell walls, and chiral biopolymers. These self-organized helical structures produce unique optical properties, giving rise to the selective Bragg reflection of colorful light. In this Letter, we focus on the focal conic state of cholesteric liquid crystals and report on stable, tunable, and reversible color switching among red, green, and blue in polymer-stabilized cholesteric films. The experimental results indicate that, with appropriate voltage pulses, the electrically induced color switching of all six routes can be realized in a single cell reflecting green light. The scattered transmissive color persists at zero voltage due to the polymer stabilization.