Helical structures exist universally, from the scale of a galaxy down to very tiny molecular assembling systems such as DNA.
Wei Hu (Nanjing University), Lu-Jian Chen (Xiamen University), and co-workers have now shown how it is possible to employ a dynamic photo-alignment technique to rationally design and arbitrarily arrange the in-plane helical axes of cholesteric liquid crystals. Moreover, they are able to do this over a scale of several centimeters. As the capability to manipulate the helical axes of cholesteric liquid crystals is significantly extended, the growth of unique fingerprint textures, including spiral and wave-like continuous gratings, are demonstrated easily.
Such hierarchical superstructures are quite promising for applications such as non-mechanical beam-steering devices and lithography masks. The proposed technique shows merits of producing high quality designs with excellent flexibility, and it is easy and cost-efficient, and so ideally suited to mass production. It will bring nomourse new opportunities for the design of novel advanced photonic devices based on such helical cholesteric liquid crystal superstructures.