Scientists unveiled an invisibility cloak this week at the Technology, Education and Design (TED) conference in Long Beach, Calif.

The cloak was demonstrated by Nanyang Technological University in Singapore scientist Baile Zhang. The demonstration involved a pink Post-it note enclosed in a box of calcite optical crystal. The box caused light to bend around the note, astonishing the audience when the note became invisible.

Zhang says he made the invention "just for fun."

"I just think the idea is cool," he says. "Plus, I hope this work will demonstrate that simple tools can sometimes fulfill important functions that previously required complicated methods."

This type of technology is incredibly appealing in terms of its implications, especially for military technology. It is rumored that the United States government is working on its own version of the device. Hypothetically, the technology could be used to develop new high-stealth aircraft that would be invisible to radar microwaves. A recent report in the New Journal of Physics detailed how University of Texas at Austin researchers rendered a 7.2-inch cylindrical tube invisible in light from the microwave portion of the energy spectrum.

Additionally, Zhang's work with calcite may have even more uses, including the improvement of optical cable fibers, like those used in broadband Internet cables. It could also help improve "imaging products" like digital cameras.

That said, Zhang's research still has a long way to go.

"There are still many limitations and I don't have the answers for how to solve them," he says. "At this stage, this is already the best we can do. There will be quite a long way to go before it can be applied on a practical level. But all researchers in this field, including myself, are making progress, albeit slowly."

The TED 2013 conference in Long Beach was held from Feb. 25 to Mar. 1. Its theme was "The Young. The Wise. The Undiscovered."