Photo-induced diffusion in polymerizing chiral-nematic media

Photo-assembly of reactive liquid crystals by simultaneous diffusion and po lymerization can give rise to interesting new polymeric architectures. In t his report, the authors summarize recent results, which show how deformatio n of the molecular helix in a cholesteric network can give rise to interest ing new optical properties, such as higher order reflection bands and built -in optical retardation. When the deformed helix is combined with a pitch g radient over the film thickness, the built-in retardation can be used for w ide-band cholesteric polarizers that directly generate polarized light.