Encrypted mirror prepared based on the linearization of circularly polarized light

Abstract

As optical filters, cholesteric liquid crystal polymer network (CLCN) mirrors with a broad reflection band and high reflectance have attracted considerable attention. However, applications based on other functionalities remain limited. In this work, CLCN films exhibiting a broad reflection band were fabricated via polymerization-induced diffusion of a chiral additive. This mechanism was verified by investigating the distribution of the non-reactive chiral additive during the film preparation process. A quarter-waveplate was fabricated using a nematic liquid crystal mixture and the optical alignment agent SD1, which converts circularly polarized light into linearly polarized light. By stacking CLCN films with different selective Bragg reflection bands together with a patterned quarter-waveplate, an encrypted mirror was successfully prepared. Colourful images can be observed through both linear and circular polarizers, demonstrating the potential of this patterned mirror for encryption applications.