April 23 (UPI) -- Researchers at the Georgia Institute of Technology have managed to build a cascading silicon peashooter -- a smaller, more precise atomic beam collimator.
The technology could be used to produce exotic quantum phenomena for scientists to study or to improve devices like atomic clocks or accelerometers, a smartphone component.
"A typical device you might make out of this is a next-generation gyroscope for a precision navigation system that is independent of GPS and can be used when you're out of satellite range in a remote region or traveling in space," Chandra Raman, an associate professor of physics at Georgia Tech, said in a news release.
Atomic beam collimators feature a box of atoms, typically rubidium atoms. When heated, the atoms begin to bounce around energetically. A tube connected to the box allows atoms bouncing at just the right trajectory to escape.
The atoms bounce their way down the tube and are shot out the end of the barrel like a pellet from a shotgun. And like the spray of pellets from a shotgun, the atoms form a random spray.
"Collimated atomic beams have been around for decades," Raman said, "But currently, collimators must be large in order to be precise."
Researchers managed to shrink the technology to chip-scale by carving narrow channels on a silicon wafer using lithography, the technique used to etch computer chips. The channels work like a miniature row of shotgun barrels all pointing in the same direction. The tiny channels can shoot out a precise array of atoms.
To make the array even more precise, scientists sliced a pair of tiny gaps across the channels. Atoms bouncing along at a more askew angle bounce their way out of the channels, while atoms moving parallel continue on their straighter trajectory out the end of the barrels.
Unlike a laser beam, which is composed of massless photons, a beam of atoms produced by the collimator has mass, and thus also features momentum and inertia. That allows the technology to be utilized in gyroscopes, which are used to measure motion and changes in location.
Current chip-scale gyroscopes rely on microelectromechanical systems, which are accurate in the short term but become less precise over time -- or "drift" -- as they accumulate deformities from mechanical stress.
"To eliminate that drift, you need an absolutely stable mechanism," said Farrokh Ayazi, a professor of electrical and computer engineering at Georgia Tech. "This atomic beam creates that kind of reference on a chip."
Researchers suggest the new chip-scale collimated atomic beam -- described this week in the journal Nature Communications -- could be used to create Rydberg atoms. When atoms become excited by heat, their outermost electron expands its orbit. The electron behaves like the lone electron of a hydrogen atom, while the Rydberg atom acts as if it possesses only one proton.
"You can engineer certain kinds of multi-atom quantum entanglement by using Rydberg states because the atoms interact with each other much more strongly than two atoms in the ground state," Raman said.
"Rydberg atoms could also advance future sensor technologies because they're sensitive to fluxes in force or in electronic fields smaller than an electron in scale," Ayazi said. "They could also be used in quantum information processing."
