Toward unhackable communication: Single particles of light could bring the 'quantum internet'

October 16, 2018 by Kayla Wiles
Purdue researchers have created a new light source that generates at least 35 million photons per second, increasing the speed of quantum communication. Credit: Massachusetts Institute of Technology image/Mikhail Shalaginov

Hacker attacks on everything from social media accounts to government files could be largely prevented by the advent of quantum communication, which would use particles of light called "photons" to secure information rather than a crackable code.

The problem is that quantum communication is currently limited by how much can help send securely, called a "secret bit rate." Purdue University researchers created a new technique that would 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 Simeon Bogdanov, a Purdue postdoctoral researcher in electrical and computer engineering.

Eventually, a high will enable an ultra-secure "quantum internet," a network of channels called "waveguides" that will 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, and matter are so sensitive to disturbances," Bogdanov said.

The work was first published online in July for inclusion in a print Nano Letters issue on August 8, 2018.

Using light to send information is a game of probability: Transmitting one bit of information can take multiple attempts. The more photons a light source can generate per second, the faster the rate of successful information transmission.

The Purdue University Quantum Center, including Simeon Bogdanov (left) and Sajid Choudhury (right), is investigating how to advance quantum communication for practical uses. Credit: Purdue University image/Susan Fleck
"A source might generate a lot of photons per second, but only a few of them may actually be used to transmit information, which strongly limits the speed of quantum communication," Bogdanov said.

For faster , Purdue 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 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.

The nitrogen and the missing atom together formed a so-called "nitrogen-vacancy center" in a diamond with electrons orbiting around it.

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." By the center absorbing and emitting one plasmon at a time, and the nanoantenna converting the plasmons into photons, the rate of generating photons for became dramatically faster.

"We have demonstrated the brightest single-photon source at room temperature. Usually sources with comparable brightness only operate at very low temperatures, which is impractical for implementing on computer chips that we would use at room temperature," said Vlad Shalaev, the Bob and Anne Burnett Distinguished Professor of Electrical and Computer Engineering.

Next, the researchers will be adapting this system for on-chip circuitry. This would mean connecting the plasmonic antenna with waveguides so that photons could be routed to different parts of the chip rather than radiating in all directions.

Explore further: Physicists demonstrate new method to make single photons

More information: Simeon I. Bogdanov et al. Ultrabright Room-Temperature Sub-Nanosecond Emission from Single Nitrogen-Vacancy Centers Coupled to Nanopatch Antennas, Nano Letters (2018). DOI: 10.1021/acs.nanolett.8b01415

Related Stories

Physicists demonstrate new method to make single photons

July 23, 2018

Scientists need individual photons for quantum cryptography and quantum computers. Leiden physicists have now experimentally demonstrated a new production method. Publication in Physical Review Letters on July 23rd.

Toward unbreakable encrypted messages

September 13, 2017

Chinese researchers recently announced a landmark advancement: They used a satellite orbiting Earth to beam pairs of quantum-entangled photons to two Tibetan mountaintops more than 700 miles apart. This distance blew the ...

Controlling photons with a photon

June 28, 2018

Photons are considered to be ideal information carriers and expected to play important roles in quantum communication and information processing, where quantum mechanics allows for absolutely secure cryptographic key distribution ...

Recommended for you

Directivity to improve optical devices

November 9, 2018

A team of researchers from the Dutch institute AMOLF, Western University (Canada), and the University of Texas (United States of America) recently demonstrated the use of algorithmic design to create a new type of nanophotonic ...

Graphene takes a step toward renewable fuel

November 8, 2018

Using the energy from the sun and graphene applied to the surface of cubic silicon carbide, researchers at Linköping University, Sweden, are working to develop a method to convert water and carbon dioxide to the renewable ...

Creating better devices: The etch stops here

November 8, 2018

A team of multi-disciplinary scientists and engineers at the University of Illinois at Urbana-Champaign have discovered a new, more precise, method to create nanoscale-size electromechanical devices. Their research findings ...

6 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

holoman
5 / 5 (1) Oct 16, 2018
And using resonant cavities for holographic storage and quantum data read/writes.

https://drive.goo...c06vLT90
Hyperfuzzy
1 / 5 (2) Oct 16, 2018
This is nonsense. A single point upon a sphere about any charge describes 1 Photon, i.e. nonexistent! When you recognized, it's gone. It's a lot easier to follow, by following the source. Since it actually is only a point within an infinite field about a single unique point at a unique point in time. I prefer to see it as space-time. We know what each point looks like. I use a 4D isomorphic mathematical space; let c = 1; then, T = Lambda. It's only a perspective. A computer can be more holistic. Visualize any field; at any point. Summation over time? Or do we need time?
Hyperfuzzy
1 / 5 (2) Oct 16, 2018
Units? Particles? Ghosts? Hack? What Level of design? The Fields, the Centers, Both, over nT? Whose listening; if I got this?
Hyperfuzzy
1 / 5 (2) Oct 16, 2018
Then we know how to fuzzify Lambda!
sirdumpalot
5 / 5 (1) Oct 17, 2018
Well this will make the dark web even darker!
Hyperfuzzy
not rated yet Oct 17, 2018
Well this will make the dark web even darker!

I love you guys I can count on non-funny nonsense. Being human is curable w/ logic.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.