Can Laser Treatment Rejuvenate the Incandescent Bulb?

By Eliza Strickland | June 8, 2009 1:28 pm

light bulbThe battle of the light bulb may not be quite over. While traditional incandescents will soon be phased out in the United States and abroad, researchers are plugging away to create more efficient versions that comply with looming new standards — while also providing an alternative for consumers who find compact fluorescents objectionable [The New York Times, blog]. In one new study, researchers have demonstrated how an incandescent bulb can be modified to give out much more light without requiring more power.

Lead researcher Chunlei Guo and his colleagues were experimenting with the effect of ultrafast laser pulses on metals when they noticed that pulses lasting only a few femtoseconds–quadrillionths of a second–could fundamentally change the molecular arrangement of metals without melting them [ScienceNOW Daily News]. The laser blasts caused the metal to turn black, which boosted its ability to absorb light. Because the law of thermal radiation state that materials that can absorb a great deal of energy will also emit large amounts of energy, the researchers decided to see if their laser treatment would boost the light output of the metal filament in an ordinary light bulb.

They fired a femtosecond laser beam through the glass of an off-the-shelf incandescent bulb. As expected, the lightning-fast beam rearranged the molecules of the bulb’s tungsten filament, turning it dark black. But then, when the researchers turned the bulb on, the part treated with the laser shone considerably brighter than the rest of the filament [ScienceNOW Daily News]. When they gave an entire filament the laser treatment, an altered 60-watt light bulb glowed as brightly as a 100-watt bulb, but still used its normal amount of electricity.

The findings, which will be published in the next issue of Physical Review Letters, may not be ready for commercialization just yet, but Guo believes it would not be difficult for bulb companies to add a tungsten blackening step to the manufacturing process. “The implementation should be fairly straightforward,” he said [The New York Times, blog]. However, compact-fluorescent bulbs and light-emitting diode (LED) bulbs are already on the market, and research is continuing on how to make those technologies cheaper, more pleasing to the eye, and still more efficient, so the laser treatment may not be enough to give new life to the old-fashioned light bulb.

Related Content:
80beats: Big Advance in OLED Lighting Might Signal Beginning of the End for the Bulbs
DISCOVER: Future Tech shows why the light bulb is becoming as quaint as a vacuum tube

Image: flickr / kaibara87

CATEGORIZED UNDER: Physics & Math, Technology
  • Dennis

    It stands to reason that these treated bulbs emit less heat.

  • Nick

    Dear Science what a useless improvement. Wow they made a 60 watt shine as brightly as a 100 watt. *snooze* Wake me up when they have a 25 watt outshining a 100 watt and maybe we’ll be talking – just remember though, that they waste a whole lot of energy shining light in direction’s we don’t need – who needs a bright ceiling? The same problem occurs with CFLs… that’s why my money is on LED technology, since they only put light out in the needed direction, without wasting a bunch of energy as heat (like incandescents do).

    And everyone bitching about the awful light of fluorescents has never experienced the joy of daylight-spectrum CFLs… something I learned about working in the hydroponics industry.

    Once you put a daylight CFL next to any other current bulb on the market, and see what it does for colors when the sun ain’t up… you’ll throw everything else away. I did, including my cheap but effective non-daylight CFLs (okay, gave away to people stuck on incandescent).

    If I had my old bulbs still and a couple of lamp heads, I could set up a side-by-side color comparison and take a picture of both of them simultaneously (otherwise the white-balancing would make both of them look fine) – when you have a daylight bulb (5500K for those paying attention), you can see all the colors, when you have a warm yellow or bright white (2700-3300k for yellah and about 4100k for bright-white) you definitely notice a lack of color towards the blue end of the color spectrum. After all, objects don’t have any inherent color properties, it’s a matter of what wavelengths of light they scatter – and if the wavelengths aren’t there, they can’t scatter them.

    Even if this does super-effecientize incandescents, they will still have awful color.

  • nick

    any advancement is a good one.

  • Michael

    CFLs have some significant disadvantages. They have highly toxic compounds in them, and so are not easy to dispose of safely. They should not be used in enclosed housings without ventilation as they can overheat and actually explode. They often simply don’t work in extremely cold environments. They will not dim when used with a common dimmer switch. They don’t work properly with ‘touch’ type lamp switches. Their energy/heat index is a lot better than the incandescent bulb, to be sure.

    The real solution is the LED, which is pretty expensive now, but as production and research continues the prices will come down. It’s cool, safe and efficient. It is the future of lighting.

  • YouRang

    Maybe someone working on the incandescents will remember that what is desired is to make the filament BLACK in the VISIBLE range but WHITE in the INFRARED range and in the UV range. (It is also desirable to make the outside of the glass black in the Infrared so it won’t feel hot; this is also true for CFLs.)
    Although the CFLs are an improvement over the straight ones, they still FLASH ON AND OFF AT 60 HZ. (LEDs also flash on and off at 60 Hz unfortunately.) Admittedly, incandescents brighten and dim at 60 Hz, but it is a small signal over the steady glow; and LEDs can be made to glow about as steadily as incandescents but will be the bean counters have the engineers do it? (Flashing on and off is relevant for those of us with neurological problems and maybe for everyone.)
    And they’ve had daylight flourescents in the straight line bulbs. They are way too blue to be enjoyable; YOU STILL NEED THE WHOLE SPECTRUM and daylight fluorescents merely have MORE BLUE NOT BALANCED BLUE.
    Bottom line: There is no intrinsic reason that incandescents can’t be made to radiate a spectrum that looks almost exactly like sunlight in the visible but radiates not at all in the UV and in the IR. Just how much will it cost? (“Almost exactly” since the spectrum doesn’t necessarily have absorption lines in it.)

  • Frederick

    I’m surprised that no one has mentioned the evolutionary significance of incandescent lighting!

    For the last eons of human existence, humans have seen at night with fire and it’s variations (wood, dung, whale oil, kerosene, natural gas, incandescent lighting). It has only been in the last 70 years that fluorescent lamps (and now it’s bluer cousin, LEDs) have been commercially available, the last 50 where they were only used in offices and factories (daytime) and the last 15 for use in the home’s living spaces. Is it natural for humans to see at night with artificial daylight?

    It’s only recently that the nature of light on health has been linked with such discoveries as SAD, lighting’s effect on circadian rhythms and human health and how lighting designed for energy efficiency and visual effectiveness can be disruptive to senior’s sleep patterns to name a few.

    It’s seems too soon to know what effect this change in lighting habits might have on our long term evolution or our short term health. But in the meantime Nick, gas up the Suburban and get to the home center and buy another Daylight CFL.

  • Christina Viering

    I like the daylight incandescents.

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