Search results for "Cholesteric liquid crystal"
showing 2 items of 2 documents
Distributed feedback lasing in cellulose films
2013
Cellulose derivatives, because of their molecular structure and chirality, can self-assemble to form spatially periodic cholesteric liquid crystal phases. We have synthesized and produced solid cross-linked cholesteric cellulose based films optimized to provide high reflectivity. Since these films are self-assembled photonic bandgap materials, they may be expected to show distributed feedback lasing. By doping samples with fluorescent dyes and optically pumping thin films of these materials, we were able to demonstrate, to the best of our knowledge, for the first time, mirrorless band-edge lasing in cellulose derivatives.
Tuneable multicoloured patterns from photonic cross-communication between cholesteric liquid crystal droplets
2014
Monodisperse droplets of planar-aligned cholesteric (N*) liquid crystal exhibit an intriguing capacity for photonic cross-communication, giving rise to colourful patterns that depend sensitively on the N* pitch, droplet positions and illuminated area. The phenomenon results from a combination of omnidirectional selective reflection of N* droplets—which thus act as spherically symmetric self-assembled photonic crystals—and total internal reflection at the continuous phase surface. We outline how the unique optical properties can be employed in numerous applications.