Novel Electro-optic and Photonic Behaviours in Bent Core Liquid Crystals

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Liquid crystals are self-organizing fluids that display a remarkable array of structures, each of which has subtly different physical properties. They are best known for their use in liquid crystal devices (LCD), a hugely successful technology in which cigar-shaped molecules are organized so that on average their long-axes point along a direction that can be controlled by an electric field. The ordered structure they form is birefringent, so interacts with polarized light, and LCDs result when the birefringence, and hence transmission of polarized light, is modulated by a voltage. Control of the molecular shape and structure can result in the formation of different liquid crystal phases and offer a route to control many desirable properties. In this proposal, we aim to exploit some very new research in which the molecular structure has a bent-core, leading to a new class of nematic liquid crystals with properties that can include ferroelectricity, biaxiality, enhanced flexoelectricty, unusual visco-elastic behaviour and therefore new electro-optic effects. We propose to produce such materials that are room-temperature and to generate a detailed understanding of their physical properties. We expect that this will lead us to new kinds of fast switching that could either be used in displays or indeed in other kinds of electro-optic devices. For example, we expect that some of these materials will exhibit optical nonlinearity - this means that when red light is shone into them, blue light emerges (this is known as frequency doubling), and such materials find uses in photonic devices such as lasers.The research period is a short one as we wish to make rapid use of our existing expertise in a subject area that is changing rapidly. We believe that we can carry out sufficient research in a year, using fully trained personnel in an environment where we have all of the necessary experimental methods at our fingertips, to understand which areas need further research, and which can lead immediately to technology that is ripe for transfer to our industrial colleagues via 'follow on' or other knowledge exchange mechanisms. Therefore, we expect this research programme to be very cost-effective, delivering several high-quality papers on the fundamentals of these systems, and also to lead to high impact as we transfer some of the most interesting technology to our industrial colleagues.