Glassy Liquid Crystal Films as Broadband Polarizers and Reflectors via Spatially Modulated Photoracemization

Chiral‐nematic glassy liquid crystals (GLCs) are of interest because of their unique supramolecular structure and associated optical properties. However, the constant‐pitch films produced so far have a bandwidth limited to less than 100 nm in the visible. The introduction of a pitch gradient, indicated by theory to increase bandwidth, is reported here to be achieved by the generation of a pitch gradient in the mesomorphic fluid state and subsequent thermal quenching, freezing in the pitch gradient. An increase of polarization bandwidth by a factor of 2.4 was found.