Hurricanes of light

Many elements of the modern lifestyle followed by a significant part of humanity depend on the encoding of information in some medium and its transmission. A common method is to encode the data in laser light and send it via fiber optics. The growing demand for more information capacity requires finding even more efficient ways to encode it.

Researchers have found a new way to create tiny hurricanes of light, technically light vortices, that can carry a lot of information. The method is based on the manipulation of metal nanoparticles that interact with an electric field. The method, which takes advantage of a class of geometries known as quasicrystals, was devised by Kristian Arjas and implemented experimentally by Jani Taskinen, both of Aalto University in Finland.

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

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

Now, the team of Arjas and Taskinen has devised a method to create geometric shapes that theoretically allow the creation of any type of vortex.

To achieve this, the team manipulated 100,000 metal nanoparticles, each approximately the size of one-hundredth the thickness of a human hair, forming a new and revolutionary design.

The new method, based on quasicrystals, theoretically allows the creation of any type of light vortex. (Image: Kristian Arjas/Aalto University)

This advance constitutes a key step in the development of practical applications of this phenomenon and opens the door to the possibility of finding totally new ways of transmitting information.

The Arjas and Taskinen team presents the technical details of their advance in the academic journal Nature Communications, under the title “High topological charge lasing in quasicrystals.” (Fountain: NCYT by Amazings)