Bubbly Polymer Promises Photonic Crystals

Scientists at Georgia Institute of Technology in Atlanta, North Carolina State University in Raleigh and Lucent Technologies Inc.'s Bell Laboratories in Murray Hill, N.J., may have discovered a simple means of producing photonic crystals. They describe in the April 6 issue of Science how blowing humid air over a polymer/solvent mixture produces a lattice with air pockets of a uniform diameter.

The researchers believe that the evaporation of the solvent causes water vapor to cool and condense into droplets on the surface of the solution. Because the water is more dense than the mixture, the drops sink into it. The velocity of the airflow over the surface of the solution determines the diameters of the droplets and thus the air pockets they create when they evaporate.

The team has created pockets as small as 200 nm in diameter and hopes to produce a photonic bandgap material using the technique.