Professor of optics Chunlei Guo. Photo: University of Rochester
Everything is Better with Lasers
What if you could take a regular incandescent lightbulb, zap it with a powerful laser for a small fraction of a second, and make it about twice as efficient as a regular lightbulb? That seems to be what researchers at the University of Rochester did. What does the laser do? It creates an "array of nano- and micro-scale structures on the surface of [the] regular tungsten filament—the tiny wire inside a light bulb—and these structures make the tungsten become far more effective at radiating light." Read on for more details.
Photo: James Bowe, CC
From the University of Rochester:
"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," says Chunlei Guo, associate professor of optics at the University of Rochester. "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." [...]
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.
The laser is very powerful, but the pulse is so short (in the femtosecond range - "a femtosecond is to a second what a second is to about 32 million years") that it actually requires very little energy and can even be powered from a regular wall outlet.
The team has also succeeded in making the bulb produce polarized light without the use of a filter.
Making Incandescent Bulbs Greener
If this works as well as the University of Rochester claims, it sounds like a big breakthrough to me. Once this process is commercialized and scaled, it probably would be very inexpensive and there wouldn't be any reason to keep selling regular incandescent bulbs.
In fact, if this technology can be further improved, maybe cheap incandescent bulbs will compete against CFLs in energy efficiency, minus the mercury and higher price tag. LEDs will probably still have the upper hand in longevity and directionality, but cost will probably stay higher for a while longer...
Via University of Rochester, The Register
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