Researchers at the University of Utrecht and the Technical University of Vienna create special light waves that penetrate even opaque materials as if they weren’t there at all.
Even scattered objects like clouds or sugar cubes cast shadows because they are disordered media that scatter light waves. But now, researchers at the Technical University of Vienna and Utrecht University have found a way to manipulate light waves. They pass through objects, projecting the image on the other side as clearly as if there were no obstacles at all.
A disordered medium is essentially a collection of randomly spaced particles such as powder, sand, sugar, or even a cloud. When light hits this group of tiny obstacles, it scatters in incredibly complex ways. But theoretically, if you could figure out this scattering pattern, you could manipulate the light waves so that they pass without scattering.
Researchers have recently succeeded in doing just that by using zinc oxide as the scattering medium, with the light source placed on one side and the detector on the other.
First, the team sent specific light signals through the powder and then measured how they entered the detector. Using some sophisticated mathematical techniques, it is possible to determine the scattering nature and create a specific light wave that does not change the waveform at all. The beam of light only dimmed slightly.
“As we have been able to show, there is a special class of light waves – the so-called scattering invariant light modes, which create exactly the same wave pattern on the detector, regardless of whether the light wave was sent only through the air. or it had to penetrate a complex layer of zinc oxide, ”explains Stephan Rotter, co-author of the study.
As intriguing as the idea of unimpeded penetration of light through an obstacle was, the team of scientists went even further. By correctly connecting several scattering invariant light modes, they created a light wave encoded with an image – in this case, the constellation Ursa Major – and projected it onto a detector via zinc oxide.
The new work builds on the team’s previous experiments in manipulating light waves to mask objects such as the invisibility cloak. The study could lead to new imaging techniques that allow you to see safely through the body, such as X-rays. However, there is still a lot of work to be done before such technology is implemented.