The incandescent light bulb is a hot technology in one sense-it wastes 90 percent of its energy in heat. Now, experts say, the 122-year reign of the tungsten filament may be coming to an end. Taking its place is gallium nitride, a super material that’s set to make billion-dollar waves in consumer markets from lighting to home entertainment.

First formulated more than 70 years ago, gallium nitride is a semiconductor that emits an intense blue light when electricity is passed through it. In the early 1990s, researchers at Japan’s Nichia Chemical Industries were the first to master the material, turning it into bright, long-lasting light-emitting diodes (LEDs) of any color. Now, gallium nitride LEDs are finding their way into traffic lights, huge display signs, and the tail lamps of the 2000 Cadillac DeVille.

Although these solid-state lights still aren’t as bright as incandescent bulbs, they consume just one-tenth the power and can last 100 times longer. That’s why lighting giants General Electric, Philips and Siemens are racing to turn out LEDs for home use by consumers. Together with Agilent Technologies, Philips is spending more than $150 million on its effort, known as Lumileds. “In the future, it is entirely possible that all our room lighting will use gallium nitride light sources,” predicts Gerhard Fasol, director of Eurotechnology, a high-tech consultancy in Tokyo.

Beyond better bulbs, experts say compact blue lasers made from gallium nitride will soon quadruple the amount of movies, music and data that can be packed onto optical discs such as DVDs. Nichia and Sony are leading the way with a plan to produce new CD players by 2001. Together, blue lasers and LEDs should drive the market for gallium nitride devices from $400 million today to well over $1 billion by 2006, according to Henry Rodeen, a consultant with Strategies Unlimited, a San Francisco research firm.