Though desktop 3D printers are a relatively new method of manufacturing, you might argue that they’re already at a plateau. You can print cute figurines, teacups that might have a leak, and sometimes replacement parts for certain objects, such as gears — not the most useful items in the world. However, what if you were able to 3D-print an invisibility cloak? Researchers at Duke University have done just that.
An assistant research professor in computer engineering at Duke’s Pratt School of Engineering, Yaroslav Urzhumov, and his research team created a plastic invisibility cloak using a standard 3D printer. If you’ve been following recent invisibility cloak technology, you’ll almost certainly have expected that this “cloak” isn’t some robe you can toss over yourself. Rather, it is an object that masks visibility differently than how, for example, hiding behind a wall would remove you from sight. The disk, pictured above, resembles something of a white vinyl record with holes throughout the structure. The location, shape, and size of the holes are chosen by algorithms that determine which combination of those metrics will result in a deflection of microwave beams.
When an opaque object is placed into the center of the disk — which has an open hole like the aforementioned vinyl record — then microwave beams are shot at it, the beams do not detect the object. The design of the rig essentially grabs the microwave beams, then a dielectric shell slings them around the disk and into the space that isn’t occupied by the opaque object.
Perhaps disappointingly, the current version of the disk doesn’t deflect wavelengths higher than microwave beams, which includes visible light. However, Urzhumov feels this current iteration of invisibility technology will pave the way for optical cloaking — the effect we all initially imagine when discussing an invisibility cloak. He claims to have run computer simulations that prove the technique can be applied to larger objects, as well as can produce cloaks around one-inch thin, making the cloaks more versatile.
The cloaking disk is made using a standard 3D printer, and takes anywhere from three to seven hours to print. Urzhumov says the device can literally be made by a printer that only costs a couple thousand dollars — not an uncommon price for an “affordable” 3D printer. This means — if you had the schematics, of course — that you could load a model into your 3D printer before you go to work, and have an invisibility disk by the time you get home. At the moment, though, that’ll only help if you carefully place an object you want to hide behind the hole, and if you’re trying to hide it from microwave beams. Your roommate will have an easy time noticing it, for now.
Research paper: doi:10.1364/OL.38.001606 – “Thin low-loss dielectric coatings for free-space cloaking”