Scientists at Lucent Technologies in Murray Hill, N.J., and The Netherlands' Utrecht University have discovered how to "trick" billions of glass spheres, each about as wide as one wave of visible light, into forming 3-D optical gratings. Researchers hope these gratings will lead to new forms of optical switches and filters, and more efficient lasers, but they caution that practical applications are still in the development stage. The trick, says Lucent, was to cause the beads to form a square shape, with every layer above its predecessor. By putting a template of small squares at the bottom of a liquid suspension, the beads settled through the liquid into the useful, square formations.
Photosensitizers