Optics researchers have learned how to use lasers to inscribe nanoscale patterns into the surface of metals, thereby changing their color without having to use filters that cut down on light. One etched pattern creates the ideal "black body" that radiates all wavelengths equally, which the researchers tried on a tungsten lightbulb filament, resulting in a significant boost in efficiency. Will high-efficiency incandescent bulbs make a comeback against emerging solid-state lighting? I give them 50/50 odds. R.C.J.
Using ultrafast lasers to inscribe nanoscale patterns on the filaments of standard incandescent lightbulbs, researchers at the University of Rochester (N.Y.) were able to increase the bulbs' light-emitting efficiency dramatically, letting a 60-watt bulb shine as brightly as one rated for 100 W. The nanoscale patterns make the tungsten lightbulb filament a "black body" that is much more efficient at radiating light. Now the team is working to tailor the color of incandescent bulb filaments, not only to boost their efficiency but also to enable their light emission spectrum to be customized for different applications.