Purdue University researchers have invented a new quantum technique to keep information from being hacked.
The new technique uses particles of light called ‘photons’ to secure information rather than a crackable code. This could in turn make social media accounts and government files a lot secure.
Quantum communication is currently limited by how much information single photons can help send securely through a process called a ‘secret bit rate.’
Purdue’s new technique has successfully managed to increase the secret bit rate 100-fold, to over 35 million photons per second.
“Increasing the bit rate allows us to use single photons for sending not just a sentence a second, but rather a relatively large piece of information with extreme security, like a megabyte-sized file,” said postdoctoral researcher Simeon Bogdanov.
The end-goal is to create a high bit rate enabling an ultra-secure ‘quantum internet’ with a network of channels called ‘waveguides.’
These waveguides could then transmit single photons between devices, chips, places or parties capable of processing quantum information.
“No matter how computationally advanced a hacker is, it would be basically impossible by the laws of physics to interfere with these quantum communication channels without being detected, since at the quantum level, light and matter are so sensitive to disturbances,” Bogdanov said.
For faster quantum communication, the researchers modified the way in which a light pulse from a laser beam excites electrons in a man-made ‘defect,’ or local disturbance in a crystal lattice, and then how this defect emits one photon at a time.
The researchers sped up these processes by creating a new light source that includes a tiny diamond only 10 nanometers big, sandwiched between a silver cube and silver film.
Within the nanodiamond, they identified a single defect, resulting from one atom of carbon being replaced by nitrogen and a vacancy left by a missing adjacent carbon atom.
A metallic antenna coupled to this defect facilitated the interaction of photons with the orbiting electrons of the nitrogen-vacancy center, through hybrid light-matter particles called ‘plasmons.’
According to the researchers, the rate of generating photons becomes faster when the center absorbs and emits one plasmon at a time, while the nanoantenna converts the plasmons into photons.
MIT image/Mikhail Shalaginov/Purdue