Designfax weekly eMagazine

Subscribe Today!

Archives

View Archives

Partners

Manufacturing Center
Product Spotlight

Modern Applications News
Metalworking Ideas For
Today's Job Shops

Tooling and Production
Strategies for large
metalworking plants

Storm in a laser beam: 'Light hurricanes' may transport huge amounts of data

Much of modern life depends on the coding of information onto a means of delivering it. A common method is to encode data in laser light and send it through optic cables. The increasing demand for more information capacity demands that we constantly find better ways of encoding it.

Researchers in Finland at Aalto University's Department of Applied Physics found a new way to create tiny hurricanes of light -- known to scientists as vortices -- that can carry information. The technology is based on manipulating metallic nanoparticles that interact with an electric field. The design method, belonging to a class of geometries known as quasicrystals, was thought up by Doctoral Researcher Kristian Arjas and experimentally realized by Doctoral Researcher Jani Taskinen, both from Professor Paivi Torma's Quantum Dynamics group.

A new quasicrystal design method allows for theoretically any kind of vortex when packaging light for transmission through and optical fiber. [Credit: Kristian Arjas/Courtesy of Aalto University]

 

 

The discovery represents a fundamental step forward in physics and carries the potential for entirely new ways of transmitting information.

Halfway between order and chaos
A vortex is, in this case, like a hurricane that occurs in a beam of light, where a calm and dark center is surrounded by a ring of bright light. Just like the eye of a hurricane is calm due to the winds around it blowing in different directions, the eye of the vortex is dark due to the electric field of bright light pointing to different directions on different sides of the beam.

Previous physics research has connected what kind of vortices can appear with how much symmetry there is in the structure that produces them. For example, if particles in the nanoscale are arranged in squares, the produced light has a single vortex; hexagons produce a double vortex, and so on. More complex vortices require at least octagonal shapes.

Now Arjas, Taskinen, and the team unlocked a method for creating geometric shapes that theoretically support any kind of vortex.

"This research is on the relationship between the symmetry and the rotationality of the vortex, i.e., what kinds of vortices we can generate with what kinds of symmetries. Our quasicrystal design is halfway between order and chaos," Torma says.

Good vibrations
In their new study, the group manipulated 100,000 metallic nanoparticles, each roughly the size of a hundredth of a single strand of human hair, to create their unique design. The key lay in finding where the particles interacted with the desired electric field the least instead of the most.

"An electrical field has hotspots of high vibration and spots where it is essentially dead. We introduced particles into the dead spots, which shut down everything else and allowed us to select the field with the most interesting properties for applications," Taskinen says.

The discovery opens a wealth of future research in the very active field of topological study of light. It also represents the early steps for a powerful way of transmitting information in domains where light is needed to send encoded information, including telecommunications.

"We could, for example, send these vortices down optic fiber cables and unpack them at the destination. This would allow us to store our information into a much smaller space and transmit much more information at once. An optimistic guess for how much that would be is eight to 16 times the information we can now deliver over optic fiber," Arjas says.

Practical applications and scalability of the team's design are likely to take years of engineering. The Quantum Dynamics group at Aalto is also busy with research into superconductivity and improving organic LEDs.

The group used the OtaNano research infrastructure for nano-, micro-, and quantum technologies in their pioneering study.

The research was published early November in Nature Communications.

Source: Aalto University

Published November 2024

Rate this article