Sometimes scientific developments reflect speculative fiction. Robots and space exploration, for example, existed in science fiction long before they did in the real world. Invisibility has literary roots dating back millennia, and now it’s finally starting to make an appearance, so to speak, in the real world.
Scientists around the world have been working on cloaking devices or invisibility cloaks to render objects invisible, at least to the naked eye. They’ve met with limited success, and have created some devices of this sort, but they are usually very small, and only capable of cloaking tiny objects. Not too impressive, especially to children.
However, a team at the Karlsruhe Institute of Technology (KIT) in Karlsruhe, Germany has developed a cloaking device that’s actually large enough to show off. The device can cloak a small object by diverting light around it, the same basic principle as other cloaking devices. It does this by placing the object within a metal tube that has been painted with acrylic paint, which diffusely reflects light. Then, the tube is set within an organic polymer that has been doped with titanium, to help it scatter light.
The effect is that light is essentially slowed within the block, allowing it to be sped up again to go around the object. The way cloaking devices generally work is that they redirect light around an object, so that it can’t be seen, because we see something when it reflects light into our eyes. The problem is that in sending light around an object, scientists have to compensate for the increased time it takes, and changing the speed of light is normally impossible. What this device does is scatter that light to slow it down, and then direct it around the object at something approaching normal speed.
The result is that you can make an object invisible, and it’s easy to show off with just a flashlight and a dim room. They can’t hide a human, but the researchers hope that such displays might help get students interested in physics.