Laser doubles brightness of bulb filaments

Monday, 01 June 2009, 15:14 IST
Printer Print Email Email
Washington: An ultra-powerful laser not only doubles the brightness of light bulbs filaments but also slashes their power consumption, according to a new study. "We've been experimenting with the way ultra-fast lasers change metals, and we wondered what would happen if we trained the laser on a filament," said Chunlei Guo, associate professor of optics at the University of Rochester, who led the research. "We fired the laser beam right through the glass of the bulb and altered a small area on the filament. When we lit the bulb, we could actually see this one patch was clearly brighter than the rest of the filament, but there was no change in the bulb's energy usage." The key to creating the super-filament is an ultra-brief, ultra-intense beam of light called a femtosecond laser pulse. The laser burst lasts only a few quadrillionths of a second. To get a grasp of that kind of speed, consider that a femtosecond is to a second what a second is to about 32 million years. During its brief burst, Guo's laser unleashes as much power as the entire grid of North America onto a spot the size of a needle point. That intense blast forces the surface of the metal to form nanostructures and microstructures that dramatically alter how efficiently light can radiate from the filament, said a Rochester release. Though Guo cannot yet make a simple bulb shine pure blue, for instance, he can change the overall radiated spectrum so that the tungsten, which normally radiates a yellowish light, could radiate a more purely white light. The findings are slated for publication in an upcoming issue of the Physical Review Letters.
Source: IANS
siliconindia