Cholesteric Liquid Crystal Materials for TunablernDiffractive Optics

摘要

Modern optics and photonics constantly require break-through materialsnand designs in order to achieve miniature, lightweight, highly tunable, andneffective optical devices. One of the basic optical components is the diffractionngrating (DG), widely used for the dispersion of light, beam steering, etc.nThis review gathers research efforts on diffractive optical elements basednon cholesteric liquid crystal (CLC) materials with a supramolecular helicalnarchitecture. All main types and fabrication approaches of periodic diffractivenstructures from CLCs are classified and described. Key optical propertiesnof DGs, their advantages and drawbacks are considered. Special attentionnis paid on the tunability of DGs including design principles and prospectivenchiral materials. The review consists of three parts divided according to thenformation mechanism of diffractive structures: i) the spontaneously formednperiodic structures from CLCs confined in cells with hybrid or homeotropicnboundary conditions; ii) DGs generated by external electric field applied tonCLCs layers; iii) light-generated DGs (e.g., obtained by holography, masknexposure, photoalignment). The review also aims to initiate and gain collaborationsnbetween physicists, engineers and organic chemists to combine novelnchiral photoswitches and molecular motors with sophisticated optical designnpaving the way towards novel smart optical materials.