(October 13, 2014) Duke University researchers have made
fluorescent molecules emit photons of light 1,000 times faster than
normal—setting a speed record and making an important step toward realizing
superfast light emitting diodes (LEDs) and quantum cryptography.
This year's Nobel Prize in
physics was awarded for the discovery of how to make blue LEDs, allowing
everything from more efficient light bulbs to video screens. While the
discovery has had an enormous impact on lighting and displays, the slow speed
with which LEDs can be turned on and off has limited their use as a light
source in light-based telecommunications.
In an LED, atoms can be forced to
emit roughly 10 million photons in the blink of an eye. Modern
telecommunications systems, however, operate nearly a thousand times faster. To
make future light-based communications using LEDs practical, researchers must
get photon-emitting materials up to speed.
In a new study, engineers from
Duke increased the photon emission rate of fluorescent molecules to record
levels by sandwiching them between metal nanocubes and a gold film.
The results appear online October
12 in Nature Photonics.
“One of the applications we’re
targeting with this research is ultrafast LEDs,” said Maiken Mikkelsen, an
assistant professor of electrical and computer engineering and physics at Duke.
“While future devices might not use this exact approach, the underlying physics
will be crucial.”