The've figgured out how to take any frequency of light and changed it to any other frequency of light with near 100 percent efficency.
That means they can take green light, and make it red, or red light, and make it green. Or blue. Or any frequency they desire.
From the article: If the effect can be harnessed, it will revolutionise a range of fields � turning heat into light, for example, or prized terahertz rays.
Right now the way we typicaly deal with light and colors is we use white light and pass it through a filter, or gel, which blocks certian frequencies of light and passes others. Thus a white light can be turned green via a green gel. But going back the other way (green to white) "involves sending an extremely intense light pulse �with a power of many megawatts or even gigawatts �along next to it. This interacts with the first beam and alters its frequency, but the technique is expensive, requires high-power equipment, and is generally pretty inefficient."
Now they've discovered a way to use something called a photonic crystal to accomplish the trick. "They are used to steer light through circuits in the same way that electronic circuits direct electric current. From computer simulations, the team found that shock waves passing through a crystal alter its properties as they compress it. For example, a crystal that normally allows red light through but reflects green light might become transparent to green light and reflect red light instead.
The researchers worked out that if a photonic crystal is designed in a certain way, incoming light can get trapped at the shock wave boundary, bouncing back and forth between the compressed part of the crystal and the uncompressed part, in a "hall of mirrors" effect.
Because the shock wave is moving through the crystal, the light gets Doppler shifted each time it bounces off it. If the shock wave is travelling in the opposite direction to the light, the light's frequency will get higher with each bounce, while if it travelling in the same direction, the frequency drops."
Talk about facinating research!!! The implications of this changes everything about how we deal with light. The article gives one example of a fiber cable with many frequencies of light being bounced down it. "If a particular frequency is being used to capacity, then optical switches could shift light beams to a frequency where there is still capacity to spare."
I also thought it was interesting that right now they're doing their research by generating a shockwave by shooting a bullet(!) at the crystal. This destroys the crystal, but not before the effects can be observed.