Optical manipulation of defects in a lyotropic lamellar phase.

Here we study the line defect in a hyperswollen lamellar phase of lyotropic liquid crystal by applying a laser trapping method. We have succeeded in directly measuring the tension of a single isolated line defect and the adhesion energy between two defects. We demonstrate a new possibility of intentional patterning of various defects by direct optical manipulation. Furthermore, local rheological measurements provide information on the membrane organization around a particle and also evidence suggesting that flow in a lamellar phase has a two-dimensional nature.