Researchers Form Liquid-Light Theory

Stuart M. Hutson

Beams of light can be collimated, split or chirped -- and now, some researchers say they can even be liquefied.

Based on the assumption that a laser beam can be thought of as a gaseous stream of photons, the researchers, from the Universidade de Vigo and the Universidade de Santiago de Compostela, both in Spain, and Chalmers University of Technology in Göteborg, Sweden, have developed a theory that high-energy laser light can form into a condensed state and exhibit physical properties resembling those of a liquid.

Researchers hypothesize that one way in which pulses of light could act like liquid is by the formation of eddies when multiple "droplets" of light simultaneously reach an optical barrier. Courtesy of Humberto Michinel.

They hypothesize that, if the refractive change in a Kerr-like material becomes saturated when the beam passing through it reaches a high enough power, the beam could become concentrated to a state in which it would interact with obstacles in a manner similar to that of a liquid stream. They relate the concentration to the condensation of water droplets from a gas because of van der Waals forces.

The researchers report that they employed computer simulations to demonstrate that pulses of such light would exhibit properties that are similar to the surface tension of a water droplet. Theoretically, similar phenomena should occur in quantum fluids such as Bose-Einstein condensates.