Broadband Encrypted Mirror Fabricated via Stacking Cholesteric Liquid Crystal Polymer Network Films and a Patterned...

Cholesteric liquid crystal polymer network (CLCN) mirrors featuring a broad reflection band have attracted considerable interest for use in optical filters and decorative applications. To date, however, the development of mirrors with encryption capabilities remains unexplored. In this work, a series of chiral additives were synthesized from isosorbide and 4'-n-alkyl-(1,1'-biphenyl)-4-carboxylic acids. Using polymerization-induced chiral additive diffusion, we then prepared a set of CLCN films exhibiting broad reflection bands. By stacking these films with an optically clear adhesive, a broadband CLCN mirror with high reflectance was fabricated. Furthermore, a patterned half-wave plate was fabricated using a nematic liquid crystal polymer network (NLCN) in combination with a CLCN. A modified mirror was constructed by incorporating the patterned half-wave plate during the stacking process. When illuminated with circularly polarized light, this configuration revealed vivid colored images. These results demonstrate the potential of such mirrors for encryption purposes.