Invisibility cube | crystals to bend light and make objects disappear

Lately, it seems like you can’t click on a handful of links on the internet without running into some kind of prototype invisibility cloak. Though this device can now be added to that list, it’s more like a cube than a cloak, and something out of the ordinary — even for a notion that is as abnormal as becoming invisibile.

Invisibility cloaks seem to run rampant nowadays, but even though they’re “common,” none of them are like what you see in the movies. There isn’t a thin sheet of fabric that you can toss over your head and then completely disappear, with your arm becoming visible when you reach out from under the cloak to grab something. Recently, at TED2013 in Long Beach, California, assistant professor of physics at Singapore’s Nanyang Technological University, Baile Zhang, showed off a little device that has the same outcome of an invisibility cloak, but isn’t a cloak in the least. The device is a little cube, only a few inches in height, but ably performs its function. Zhang seems to be using the term “cloak” not to refer to the garb, but the action.

As the video shows, the demonstration involves a little cube that is placed in front of a rolled-up pink Post-it, and completely masks the portion of the paper that the cube is maneuvered in front of. The cube itself is also hidden, or else there wouldn’t so much be invisibility, as there would be more of an opaque wall.
Zhang stated that the invisibility cube is made of two pieces of calcite that are cemented to one another. Calcite is a crystal found in nature in a variety of forms, from stalactites and stalagmites, to veins of deposits in hot springs. The crystals can be either transparent or opaque, and affect light in such a way that it not only subdues shadows, but bends light around an object in order to make the object “disappear.”
The above video was not the demonstration shown at TED2013, but reports from the conference state that the demo worked the same way and produced the same result. Zhang has been working on his invisibility cube since 2010, but the TED2013 demo was the first time it was shown off in public. He said he didn’t create the cube for any specific purpose, and in theory, is looking to make it as big as he can.
In its current state — if Zhang is able to increase the size — it’s obviously not practical enough to be used as some kind of masking device. Carrying around a large cube isn’t conducive to performing a stealth operation. However, go watch the video again. Isn’t that neat? At the very least, Zhang’s calcite cube could be an early step toward some kind of wearable garb.