Those who’ve ever been interested in origami, math or just killing time are likely familiar with the Möbius strip. A Möbius strip is made by taking a single piece of paper, twisting it once and then attaching the paper’s two ends together. The result is the transformation of a two-sided object into a “non-orientable, one sided” geometry.
While making a Möbius strip out of paper is a simply matter, doing so with light is very complex.
In order to contort photons into the Möbius shape, Rochester engineers used a tightly focused laser beam called structured light. According to researchers, structured light has a specific polarization and intensity distribution, meaning that the beam’s electromagnetic (EM) field behaves differently than it would in a traditional laser.
In your everyday laser, EM radiation moves at a right angle to the beam’s path. In a structured beam, however, EM radiation isn’t restricted, meaning it can move in all three dimensions.
To build their structured light medium, engineers shot a traditional laser beam through a liquid crystal lens. After exiting the other side of the liquid crystal boundary the beam had been transformed into its structured self.
As the beam travelled through the experiment’s bounds it encountered a precisely positioned nanoparticle that researchers used as an inferometer to measure the scattering of light produced by the structured beam’s collision. From their observations researchers saw the distinct patterns of the Möbius strip emerging in the beam’s shape.
“This is one of the very few known examples of a Möbius structure appearing in nature,” states Robert W. Boyd, Professor of Optics and Physics at the University of Rochester.
While the practical application of a structured light Möbius strip is still unclear, researchers believe the underlying principles may give engineers more tools to manipulate particles on the nanoscale, particularly when it comes to other forms of light.
Who knows, a new generation of lasers and optical systems may be born of this bizarre phenomenon, or maybe they won’t. Regardless, given how fascinating this simple piece of geometry is, I can only imagine that it’s even more alluring when made of something as spectral as light.
Source: University of Rochester