Liquid crystal emits polarized light.

Sunglasses designed to cut down glare typically use polarizing lenses to prevent unwanted light waves from reaching the eyes. Many electronic-display technologies use similar filters to polarize light and create crisp, vibrant images. Because they achieve this effect by subtracting out more than half of incoming light, however, these filters end up wasting much energy.

Now, Shaw H. Chen of the University of Rochester (N.Y.) and his colleagues have created a material that generates a type of polarized light without the need for filters. They predict that it could be used to make more energy-efficient monitors, stereoscopic three-dimensional displays, and information-storage devices.

The material combines a transparent liquid-crystal film with a dye that glows blue under ultraviolet illumination. The liquid-crystal molecules line up in horizontal planes, which are stacked with each plane slightly rotated with respect to the one below. The dye molecules are embedded between the liquid-crystal molecules. As light emitted by the dye molecules traverses the planes, it becomes circularly polarized--the light's electric field rotates either clockwise or counterclockwise along its direction of travel.

Armed with the new material, "we'd like to explore the unique features of circularly polarized light for new applications," says Chen. He and his colleagues report their findings in the Feb. 11 NATURE.

The material's novel molecular structure challenges the typical notion of a liquid crystal, says Chen. "Conventional liquid crystals are fluid at room temperature. This is a glassy solid." Yet the material also does not fit the usual definition of a glass. Instead of assuming an amorphous structure, the molecules arrange themselves in an orderly fashion. Perhaps now researchers will have to broaden the definition of a glass to include any noncrystalline material, Chen suggests.