Original URL: http://www.theregister.co.uk/2009/06/01/light_bulb_laser_blast_enhancement/

Boffins: Ordinary lightbulbs can be made efficient, cheaply

Incandescents nearing extinction: Impeccable timing, everyone

By Lewis Page

Posted in Science, 1st June 2009 11:03 GMT

Just as authorities in much of the Western world have moved to phase out the incandescent lightbulb, American boffins believe they have developed a process which can make the oldschool lights more efficient than energy-saving lamps.

Optics boffins at the Rochester Uni in New York state say they've developed a process in which an ordinary lighbulb is zapped with a femtosecond-long pulse of extremely high-energy laser light. The laser blast travels through the glass to hit the tungsten filament, causing complex nano- and micro-structures to form on its surface.

Once the lasered light bulb is than powered up, according to the Rochester scientists, it emits a lot more light for the same energy compared to an untreated bulb - equivalent to 40 per cent energy savings. The process of lasing incandescent bulbs wouldn't be expensive, apparently, so they'd remain cheap compared to fluorescent energy-saving jobs.

According to Rochester Uni:

The process could make a light as bright as a 100-watt bulb consume less electricity than a 60-watt bulb while remaining far cheaper and radiating a more pleasant light than a fluorescent bulb. Despite the incredible intensity involved, the femtosecond laser can be powered by a simple wall outlet, meaning that when the process is refined, implementing it to augment regular light bulbs should be relatively simple.

It seems that Professor Chunlei Guo of Rochester hit upon the idea of brightening-up lightbulb filaments following earlier experiments in which he and his team used laser zapping to turn metals completely black. This worked so well that Guo and his cohorts wondered if they could reverse the process.

"We fired the laser beam right through the glass of the bulb and altered a small area on the filament," says the prof. "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."

It seems that Guo and his team of lightbulb-blasting boffins can also produce other strange effects, getting incandescent bulbs to emit partially polarised or differently-coloured light - without the energy-wasting filters that would normally be necessary.

It's the efficiency-enhancement aspect of the studies which could make headlines, however. Both the US and European Union governments are now committed to firm timetables which will see incandescent bulbs phased out in favour of more energy-efficient alternatives, such as fluorescents. This is being done in order to save energy and so lower carbon emissions. But if it's as simple as Guo suggests to enhance an incandescent with his laser process, this may turn out to have been an unnecessary or even retrograde step.

Guo's research has been accepted for publication by the journal Applied Physics Letters, but isn't out yet. In the meantime, there's a pop-sci release from the university here. ®