Oregon scientists blast photons with green lasers

Oregon scientists blast photons with green lasers »Play Video

EUGENE, Ore. - Scientists at the University of Oregon recently made a breakthrough in quantum physics that promises to change the Internet as we've known it, increasing the capacity of fiber optic communications and making networks more secure. 

The key technology: blast a single photon with lasers to change its color.

"The way that we changed the color of a single photon is that we focused that photon on to the end of an optic fiber," explained Michael Raymer, Professor of Physics at the University of Oregon.

"At the same time we focus two strong laser pulses into the same fiber," he said.

"These two strong laser pulses, which have different colors than the single photon, which is a very weak pulse of light, those two strong laser pulses exchange a little bit of energy with our one photon."

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A photon is most simply described as a particle of light.

There are many types of quantum particles.

Some particles make up matter, like protons, neutrons and electrons. Other particles transmit forces, like gravity or the electro magnetic force. 

Each force has its own transmitter particle. The electromagnetic force is transmitted by the photon. Visible light, being part of the electromagnetic spectrum, is made up of photons.

Changing the color of a photon means fewer photons are needed to carry a bit of information.

"In the future what we'd like to be able to do is to send these bits across the Internet using a single photon for each bit rather than 1,000 photons for each bit," Raymer said.

It is hard to say for sure what technological advancements could result from this discovery, but these UO scientists say they are in it for the science.

"You're digging and digging and you're getting all fustrated," Raymer said, "but when you finally find that nugget of new information its just like a diamond and its very exciting."

"A given photon can be either red or green, for example,"  Raymer said, "or according to the strange laws of Quantum Mechanics, you can say that this particular photon is neither green or red. It has the potentiality to be either green or red; if you measure its color you'll observe either green or red.

"But before you measure it, it's really not valid to say the photon had one color or the other. And this is what we call quantum superposition," the professor said. "And it's this strange property that allows you to ensure that the communications is very secure. Because if an eavesdropper intercepts this photon and tries to determine if its red or green or both or neither, then the eavesdropper will disturb the state of that particle and that's called the Heisenberg's Uncertainty Principle that anytime you measure a quantum system you change the system, and it's this change which allows the legitimate user of the communications channel to detect the fact that the eavesdropper was present."

The technique can also help pack more info into fewer photons.