What do you get when you combine red, blue, green, and yellow diode lasers?
Apparently, pretty fantastic-looking warm white light. Researchers at Sandia National Laboratories recently produced a white light made from lasers and tested it out on a bowl of fruit. The results were incredibly surprising.
Lighting experts have assumed in the past that diode lasers would be a poor source for creating white light. Lasers emit single, narrow wavelengths (very different from the sun’s broad spectral bands). Researcher Jeff Tsao explained,
Before these tests, our research in this direction was stopped before it could get started. The typical response was, ‘Are you kidding? The color rendering quality of white light produced by diode lasers would be terrible.’ So finally it seemed like, in order to go further, one really had to answer this very basic question first.
And answer it they did. Forty volunteers came into the lab to report which light source they preferred on two identical bowls of fruit. The laser lights were compared with standard incandescent light bulbs, neutral LEDs, and warm and cool LEDs. Volunteers actually preferred the diode laser lights over the warm and cool LED lights. And when it came to the neutral LEDs and the standard incandescent light bulbs, there was no statistically significant preference.
The volunteers essentially couldn’t tell the difference between incandescent light bulbs and laser-based lights. In an age when the lighting industry is very centered around creating alternative light sources that emulate incandescent light, that’s an exciting discovery.
Want to try the experiment? Click on the photo to zoom in, and try to determine which light source is the incandescent.
Note that the process of creating diode lasers is more expensive than LEDs at this time. However, Sandia Labs will continue researching and developing this lighting possibility.
As far as the photo: The fruit bowl lit with lasers is on the left, and the standard incandescent bulb lights the fruit on the right. Did you guess correctly?
Photos and quote courtesy of the news release from Sandia Labs