Optical Camouflage ―Tunable Coloration Accompanied by Optical Janus Effect

Abstract

A scalable, massive, tunable, and viewing-direction sensitive asymmetric coloration based on optical Janus effect is highly demanded for advanced color displays enabling asymmetric information delivery, but dynamic color controls toward viewing directionselective information invisibility remains long-standing challenges. We designed a single unit of Fabry-Perot etalon and realized completely new and exotic chromatically switchable phenomenon, which exhibits color difference across the viewing directions accompanied with message displaying/hiding in direction-sensitive manner depending on different liquid immersions, called optical camouflage. Our color tunable platform opens up opportunities for a wide range of applications in art, optical switch, color displays, and security features in anti-counterfeiting devices.