Cornell Researchers Create a Wrinkle In Time
We’ve talked about military-related research into invisibility cloaks on this blog before; now the Pentagon and some researchers at Cornell are looking at ways to mask entire events as they happen. The technology not only has implications for military operations, but also new types of light-based photonic chipsets.
The Cornell University researchers published a paper in Nature explaining how they managed to hide an event for 40 trillionths of a second. This spatio-temporal cloaking method slows down the flow of light from events, rendering them invisible. The research was funded by DARPA.
In the experiment, researchers split a beam of light traveling through a fiber-optic cable into one slow and one fast beam, then fired a red laser through the same space. The laser was not observable for several picoseconds. According to the article:
This approach is based on accelerating the front part of a probe light beam and slowing down its rear part to create a well controlled temporal gap—inside which an event occurs—such that the probe beam is not modified in any way by the event. The probe beam is then restored to its original form by the reverse manipulation of the dispersion.
In other words, the researchers created a gap in the beam of light, the event then took place in that gap, and the beam was reconstituted afterward.
It could be awhile before this technology exists in any practical form; according to the folks at Cornell, masking an event for a single second would require a machine 18,600 miles long. However, the technology could allow someone to insert an emergency signal into a data stream, or provide a method for multitasking operations in a photonic computer.
The experiment was based on an idea originally published by Martin McCall, a professor of physics at the Imperial College in London.
“But his method required an optical response from a material that does not exist,” said Alexander Gaeta, professor of applied and engineering physics at Cornell. “Now we’ve done it in one spatial dimension. Extending it to two [that is, hiding a moment in an entire scene] is not out of the realm of possibility. All advances have to start from somewhere.”
You can view a simulation video below:
Source: Cornell University