Laser Induces Patterns in Polymer Solutions

Researchers from the Institute of Electronic Structure and Laser and the University of Athens, both in Greece, and the Max Planck Institute for Polymer Research in Mainz, Germany, have reported the formation of patterns in homogeneous polymer solutions induced by a low-power, CW visible laser. Their findings are described in the July 5 issue of Science.

They trained a red krypton-ion laser onto optical cells containing various polymer solutions and directly observed both profile modifications of the laser on a screen and a smooth beam trace using dark-field coherent microscopy and a CCD camera. Most polymer solutions scatter low-power laser light. However, when the scientists applied the laser to a solution of poly(isoprene-1,4) in n-hexane, they observed a richly structured pattern. Concurrently, dark-field imaging revealed stable stringlike and dotlike patterns in the solution parallel to the laser beam propagation direction.
The team continues to investigate the phenomenon. The technological importance of light-matter interactions indicates that these observations could lead to photorefractive, micro-optics and nanotechnology applications.