from the light-reading dept.
How do we make an object invisible? Researchers from TU Wien (Vienna), together with colleagues from Greece and the USA, have now developed a new idea for a cloaking technology. A completely opaque material is irradiated from above with a specific wave pattern – with the effect that light waves from the left can now pass through the material without any obstruction. This surprising result opens up completely new possibilities for active camouflage. The idea can be applied to different kinds of waves, it should work with sound waves just as well as with light waves. Experiments are already in the planning.
[...] "Complex materials such as a sugar cube are opaque, because light waves inside them are scattered multiple times," says Professor Stefan Rotter (TU Wien). "A light wave can enter and exit the object, but will never pass through the medium on a straight line. Instead, it is scattered into all possible directions."
For years many different attempts have been made to outwit this kind of scattering, creating a "cloak of invisibility." Special materials have been worked out, for example, which are able to guide light waves around an object. Alternatively, also experiments have been performed with objects that can emit light by themselves. When an electronic display sends out exactly the same light as it absorbs in the back, it can appear invisible, at least when looked at in the right angle.
At TU Wien a more fundamental approach has now been chosen. "We did not want to reroute the light waves, nor did we want to restore them with additional displays. Our goal was to guide the original light wave through the object, as if the object was not there at all," says Andre Brandstötter, one of the authors of the study. "This sounds strange, but with certain materials and using our special wave technology, it is indeed possible."
[...] More information: Konstantinos G Makris et al. Wave propagation through disordered media without backscattering and intensity variations, Light: Science & Applications (2017). DOI: 10.1038/lsa.2017.35
Just in time. We only have 150 years to perfect this before we make first contact with the Klingons.