The breakthrough focused on managing small whirlwinds of light and electromagnetic fields has the potential to change how we transmit information through cables dramatically.
Today’s world relies heavily on how we encode information to convey it. A widely used approach is encoding data into laser light and transferring it via optic cables. With a growing need for greater information capacity, we are continually seeking improved encoding methods.
Scientists from Aalto University’s Department of Applied Physics have developed a novel technique to generate tiny light whirlwinds—referred to as vortices—that can carry data. This method involves the manipulation of metallic nanoparticles engaging with an electric field. This design concept, related to a specific geometry termed quasicrystals, was conceived by Doctoral Researcher Kristian Arjas and brought to life through experiments by Doctoral Researcher Jani Taskinen, both part of Professor Päivi Törmä’s Quantum Dynamics group. This finding marks a significant advancement in physics and could lead to innovative methods of information transmission.
Half Order and Chaos
In this context, a vortex resembles a light beam hurricane, characterized by a calm, dark center enveloped by a ring of bright light. Similar to how the eye of a hurricane remains calm due to winds swirling in various directions, the vortex’s eye is dark because the electric field of the surrounding bright light points in different directions across the beam.
Past research in physics has linked the types of vortices produced to the symmetry of the underlying structure. For instance, arranging nanoscale particles in squares results in a single vortex, while hexagonal arrangements yield a double vortex, and more sophisticated vortices necessitate at least octagonal configurations.
Now, Arjas, Taskinen, and their team have discovered a way to create geometric forms that could potentially produce any kind of vortex.
“Our research explores the connection between vortex symmetry and rotation, specifically what types of vortices we can generate with varying symmetries. Our quasicrystal design strikes a balance between order and chaos,” Törmä explains.
Good Vibrations
In this research, the team manipulated 100,000 metallic nanoparticles, each approximately one-hundredth the size of a single human hair strand, to develop their distinctive structure. The crucial part was discovering points where the particles interacted with the desired electric field the least, rather than the most.
‘An electric field features areas of intense vibration and areas that are virtually inactive. We placed particles into the inactive areas, which suppressed everything else and allowed us to focus on the field with the most interesting properties for applications,’ Taskinen states.
This discovery paves the way for extensive future exploration in the vibrant field of topological studies of light. It also marks the initial steps towards a powerful new method of information transmission in sectors where light is essential for sending encoded data, such as telecommunications.
‘For instance, we could transmit these vortices through optic fiber cables and decode them at their destination. This would enable us to condense our information into a much smaller volume and transmit a significantly larger amount simultaneously. An optimistic estimate would suggest an increase of 8 to 16 times the information we can currently send over optic fiber,’ Arjas mentions.
However, the practical application and scalability of the team’s design will likely require several years of engineering development. Meanwhile, the Quantum Dynamics group at Aalto is busy researching superconductivity and enhancing organic LEDs.
The group utilized the OtaNano research facility, focusing on nano-, micro-, and quantum technologies for this groundbreaking study.
The research findings were published in early November in Nature Communications.
