An artistic impression of complex vector light that traverses distorting complex media and is altered in some way. The light pattern represents the polarization state. The complex media shown in the inserts include living tissue, submarine, fiber optics, and transmission through the atmosphere. Credit: Wits University
A team led by researchers from the University of the Witwatersrand in Johannesburg, South Africa, with collaborators from the University of Pretoria (South Africa), as well as Mexico and Scotland, has made a new discovery about how light behaves. in complex media, media. which tends to significantly distort light. They showed that “distortion” is a matter of perspective, outlining a simple rule that applies to all light and a wide range of media, including submarines, fiber optics, transmission to the atmosphere, and even through living biological samples.
His new quantum approach to the problem resolves an ongoing debate about whether some forms of light are robust or not, correcting some misconceptions in the community. It is important to note that the work describes that all light has a property that remains unchanged, a vision that contains the key to unraveling the rest of the perceived distortion. To validate the finding, the team showed robust transport through otherwise distorted systems, using the result for error-free communication through noisy channels.
Photonics of nature has published online today the research of the team led by Professor Andrew Forbes of the School of Physics at the University of Wits. In their article, the team explains the simple rules that govern the complex propagation of light in complex media. First, they find that all of these media can be treated the same and that the analysis does not depend on the type of light used. Previously, each choice of media and light beam was treated as a special case, it is no longer so: the new general theory covers everything. Second, they show that, despite distortion, there is a property of light — its “vectority” —that remains unchanged, unchanged for the media. This is always true and I hadn’t noticed it before. It holds the key to exploding light even in non-ideal conditions.
If you pass light through an imperfect medium, such as the atmosphere, it is distorted. For example, the bright mirage effect near hot roads or the twinkling of stars are both examples of light that is distorted due to the turbulence of the atmosphere. Sometimes light can also be deliberately distorted, like mirrors at an amusement fair that make you look taller, thinner, or rounder. In this case, we all understand that distortion is just a matter of perspective — a quick look at ourselves without the mirror revealing reality — but is it also true in other distorting systems? Is there any way to look at the light so that the distortion disappears? The Wits-led team proves that yes, some properties are never distorted, while others can be unraveled with a change of perspective.
The question is how to understand what is happening to the light, how it is distorted and how to find the new perspective? To answer these questions, the team used the most general form of light possible, vector light. Light has an electric field whose direction can vary across the field, sometimes pointing up, down, left, right, and so on. The “vectority” of a light is how the direction of the electric field of a light is mixed. In other words, it is a measure of how similar are the directions of the electric fields of a light in different places: if it is equal everywhere (homogeneous) the value is 0, and if it is different everywhere (non-homogeneous) the value. is 1. This vector homogeneity never changes, even if it changes the pattern of the electric field itself. Reason is embedded in quantum interlaced states, an issue that seems to have little in common with optical distortions. The new discovery was made possible by applying tools from the quantum world to the world of optical distortions.
“What we have found is that vectority is the only attribute of light that is not altered when it passes through any complex medium,” says Professor Andrew Forbes of the Wits School of Physics. “That means we have something special that can be leveraged when we use light for communications or detection.”
“This is a particular aspect of the light pattern: how the polarization pattern looks,” Forbes says. “‘Polarization’ is just a fantastic way to describe the direction of the electric field that forms light. The pattern is also distorted, but its intrinsic nature (of homogeneity or non-homogeneity) is not.”
The team’s approach allows researchers to identify how to correct any distortion through the media in a way that costs no light. In other words, there is no loss.
“We show that although light is highly distorted, distortion is only a matter of perspective. Light can be seen in such a way that it regains its original ‘undistorted’ properties. It is noteworthy that complex light in complex media can is universally understood from very simple rules “.
For example, by simply changing how a measurement is made, any communication through a highly distorted medium can be done “without distortion”. This showed that the equipment was true experimentally across a range of systems, from turbulence to liquid or optical fiber.
The perfect trap: a new way to control the polarization of light More information: Isaac Nape et al, Revealing the invariance of vector structured light in complex media, Photonics of nature (2022). DOI: 10.1038 / s41566-022-01023-w Provided by the University of Wits
Citation: light traveling in a distorting medium may appear undistorted (2022, June 24) recovered on June 24, 2022 from
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