At Harvard-MIT Center for Ulracold Atoms, a group of professors and their colleagues (led by Harvard Professor of Physics Mikhail Lukin and MIT Professor of Physics Vladan Vuletic) have turned science fiction into reality. After extensive studies, they found a way to bind photons together to form molecules, a discovery that, Lukin claims, "runs contrary to decades of accepted wisdom about the nature of light. Photons have long been described as massless particles which don't interact with each other -- shine two laser beams at each other, and they simply pass through one another..."
Luken goes on to state: "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."
Pictured is a representation of an organic molecule (shown as a yellow sphere), suspended on a photonic crystal slab (shown as a grey substrate) supporting macroscopic resonances. Image Source: phys.org
Photonic molecules, they found, are different. The team of researchers cooled a cloud of ribidium atoms in a vacuum chamber and then fired single photons into the cloud. Though the photons entered individually, they left the cloud together, as a single molecule. "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."
Lukin believes that this can eventually be used to create three-dimensional structures wholly out of light. Like crystals, or...Lightsabers.
"What it will be useful for, we don't know yet, 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," he stated excitedly.
"Photonic molecules" behave more like something you might find in science fiction
Ready to live in a world with real lightsabers? What new laws would need to be applied to own one, or would it just serve as a military weapon? Let us know you thoughts below!