Researchers from the US National Institute of Standards and Technology (NIST) have managed to create a precursor of a photon molecule, making two photons travel side by side at a specific distance.
The work is a continuation of an earlier experiment, in which a molecule of two photons with one sitting atop the other has been created.
The two experiments are important steps towards the possibility of building objects out of weightless photons.
"It's not a molecule per se, but you can imagine it as having a similar kind of structure," explained NIST's Alexey Gorshkov. "We're learning how to build complex states of light that, in turn, can be built into more complex objects. This is the first time anyone has shown how to bind two photons a finite distance apart."
In an article in the latest issue of the Physical Review Letters, the researchers explained that the arrangement binding the two photons is akin to the way that two hydrogen atoms sit next to each other in a hydrogen molecule.
"Lots of modern technologies are based on light, from communication technology to high-definition imaging," Gorshkov said. "Many of them would be greatly improved if we could engineer interactions between photons."
The finding could make it easier to calibrate sensors by creating a ‘standard candle’ shining a precise number of photons at a detector.
Furthermore, binding and entangling photons could eventually pave the way for using photons as information processors in computers.
Such computers would not only be faster, but also much more energy-efficient, the researchers said.
Currently, all data travelling in the form of light beams in fibre-optic cables have to be converted into electrons for processing. The conversion requires a lot of energy and could be completely removed if computers were able to process photons directly.
"It's a cool new way to study photons," Gorshkov said. "They're massless and fly at the speed of light. Slowing them down and binding them may show us other things we didn't know about them before."