Optical Control of Surface Anchoring and Reorientation of Liquid Crystals via a Plasmon-Enhanced Local Field

Gold nanoparticles deposited on the windows of a liquid crystal (LC) cell were found to be able to reduce the surface anchoring energy of the LC, and hence the threshold for its reorientation phase transition, by 1 to 2 orders of magnitude when a cw pump light was used to excite the local plasmon resonance of the nanoparticles. The effect was due to the disorientation of LC molecules between nanoparticles by the plasmon-enhanced local field that softens the effective surface anchoring. A light-controlled variation of surface anchoring energy could provide new opportunities for optoelectronic applications of a LC.