Scientists Make 3D Objects Invisible to Microwave Wavelengths

Researchers made a 3D object vanish from view at microwave wavelengths.

After years of progress, scientists are now coming closer and closer to making real-world objects disappear from view. Researchers from the University of Texas at Austin have made a three-dimensional object disappear from view, from any angle, at microwave wavelengths.

This latest research used plasmonic meta-materials to make an 18-inch (46-centimeter) cylindrical tube invisible. It was published by Andrea Alu et al in this week’s New Journal of Physics. Objects are visible because light rays bounce off them, hitting our retinas and allowing our brains to process the information.

Meta-materials redirect light to conceal objects, but the actual cloaking is hard. Plasmonic meta-materials cancel out the light scattering from an object. Once a cylinder is coated with these kinds of materials, they block the light rays, meaning that it becomes invisible.

Previously, meta-materials had been used to create a mirage-like effect using a panel of nanotubes that were electrically stimulated, bending the light rays. It’s a breakthrough, but before the plethora of applications are considered, researchers need to figure out how they can apply this to optical wavelengths, as their tests were performed with high-frequency wavelengths, like the microwave spectrum.

They’re pursuing their research, but making objects invisible isn’t their priority. The main application of these kinds of materials is to improve biomedical imaging.