Researchers at Sandia National Labs have mixed four different diode lasers to produce a warm, bright white light that they say is just as good as incandescents and better than LEDs. Laser light bulbs, here we come!
While the combined beam of these four lasers (red, blue, green and yellow) may be a lovely white, it's not likely that you'll see an actual white laser anytime soon. White light, being a combination of all (or at least three or four) colors, doesn't lend itself to being produced by lasers, which specialize in emitting light in single, very narrow wavelengths. For this reason, it's long been thought that lasers would never make for good white light sources: the "standard" for white light is the sun, which pumps out very broad spectral bands of light, so it seems like using just four narrow bands of color with huge spectral gaps in between would look "terrible."
As it turns out, it looks great. Really great. Once the mad scientists at Sandia had their white laser light up and running, they asked forty volunteers to participate in a test where two identical bowls of fruit in two side-by-side chambers were each randomly illuminated with warm, cool, or neutral white LEDs, a tungsten-filament incandescent light bulb, or the quad-laser white light. All the volunteers had to do is choose the one that they liked the best, without knowing what the source was. See if you can tell the difference:
Give up? The white laser light is illuminating the bowl on the left, with a standard incandescent bulb illuminating the bowl on the right.
"The result [over 3,200 trials] was that there was a statistically significant preference for the diode-laser-based white light over the warm and cool LED-based white light but no statistically significant preference between the diode-laser-based and either the neutral LED-based or incandescent white light."
So it seems like white light from lasers isn't just adequate, it's actually as good as or better than the most modern high-efficiency LED lighting that we've got now. And lasers, being awesome, are even more efficient than LEDs. They're also brighter, and directional, meaning that they'd be easy to use for precision illumination.
At this point, diode lasers are still slightly more expensive than LEDs, but some years back, LEDs were in the exact same situation relative to incandescent bulbs and CFLs, and look where we are now: LEDs are everywhere, and they've created an entirely new generation of smaller, sleeker, more efficient electronics that use LED screens. It's now looking like the next step might just be to put lasers into everything instead. Let's face it, we all knew that sooner or later that's what was gonna happen.
Via Sandia Labs