Liquid crystals are known to have interesting photorefractive properties.\u00a0 One way to induce a large photorefractive effect is to layer a liquid crystal and a photoconductor.\u00a0 Light-induced modulation of surface charge on the photoconducting layer lowers the surface energy of the liquid crystal, inducing molecular reorientation (and thus photorefraction) in the bulk of the material.\u00a0 In this project, we will attempt to intensify the observed photorefractive effect in the liquid crystal 5CB by increasing the surface charge on the photoconducting layer, using ionic polymers to increase the surface charge and gold nanoparticles to increase photoinduced charge generation through amplification of the internal electric field.\u00a0 Techniques will include dynamic holography, 4-wave mixing, and surface charge generation on a photoconductor.<\/p>\n","protected":false},"excerpt":{"rendered":"
Mark Winkler with Ken SingerSurface Mediated Photorefraction in Liquid Crystals<\/p>\n
Liquid crystals are known to have interesting photorefractive properties.\u00a0 One way to induce a large photorefractive effect is to layer a liquid crystal and a photoconductor.\u00a0 Light-induced modulation of surface charge on the photoconducting layer lowers the surface energy of the liquid crystal, inducing molecular reorientation (and thus photorefraction) in the bulk of the material.\u00a0 In this project, we will attempt to intensify the observed photorefractive effect in the liquid crystal 5CB by increasing the surface charge on the photoconducting layer, using ionic polymers to increase the surface charge and gold nanoparticles to increase photoinduced charge generation through amplification of the internal electric field.\u00a0<\/p>\n