Harvard and MIT scientists may have just brought the light saber a little closer to real-life everyday use, according to a news release.
The research team, led by Harvard physics professor Mikhail Lukin and MIT physics professor Vladan Vuletic, worked with colleagues from the Harvard-MIT Center for Ultracold Atoms on the study published Wednesday in the journal Nature.
The team was able to form "photonic molecules" by getting photons to join together to form molecules, hence the term. The photonic molecules did not behave like a regular laser, but more like the light saber of "Star Wars" fame.
"It's not an in-apt analogy to compare this to light sabers," Lukin said. "When these photons interact with each other, they're pushing against and deflect each other. The physics of what's happening in these molecules is similar to what we see in the movies."
The discovery has contradicted what has been generally accepted about light. Photons are massless particles not known to interact with each other, but when two laser beams are pointed at each other, they just pass through one another.
To get these massless particles to knit to each other, the researchers pumped rubidium atoms into a vacuum chamber. They used lasers to cool the cloud of atoms to just a few degrees about zero and began firing photons into the cloud using very weak laser pulses.
"When the photon exits the medium, its identity is preserved," Lukin said. "It's the same effect we see with refraction of light in a water glass. The light enters the water, it hands off part of its energy to the medium, and inside it exists as light and matter coupled together, but when it exits, it's still light. The process that takes place is the same it's just a bit more extreme - the light is slowed considerably, and a lot more energy is given away than during refraction."
Lukin said the team's discovery could be used in the near future in quantum computing.
"We do this for fun, and because we're pushing the frontiers of science," Lukin said. "But it feeds into the bigger picture of what we're doing because photons remain the best possible means to carry quantum information. The handicap, though, has been that photons don't interact with each other."
Even farther down the road, he said there could be three-dimensional structures made out of these light beams. Such as, say, a light saber.
"What it will be useful for we don't know yet," Lukin said, "but it's a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules' properties."
