Making White Light from Lasers
There are a variety of lighting options out there right now, including incandescent, fluorescent, and LED, but the future may add diode lasers as another. Research into modern lightning has the goal of improving efficiency, where currently LED lights rein, but they have a limit. At currents above 0.5 A the efficiency starts to drop off, so more electricity does not create as much light. Diode lasers however become more efficient as the current increases, but many scientists have felt they would be incapable of producing the color rendering quality the human eye wants. Other scientists at the DOE’s Sandia National Laboratory decided to test this claim. Combining the light from blue, green, yellow, and red diode lasers, the researchers illuminated a bowl of fruit. Similar bowls of fruit were illuminated by other light sources, including warm, cool, or neutral whites LEDs or by traditional incandescent light bulbs, and presented to participants in a study. The results showed people could tell the difference between the warm and cool LED lights, and the diode lasers, but there was no preference between the lasers, neutral LED lights or incandescent lights. While this research effectively shows lasers can be used for producing white light, we should not be expecting them to hit store shelves anytime soon. Their substrates have to be almost completely free of defects, making them expensive to make. However, the same material is also used in LED lights, so there is still a future for diode laser lights.