From Grimm’s fairy tales to Harry Potter, the cloak of invisibility has helped out of many a fictional hero. Now scientists have taken a vital step towards turning that most surreal of sartorial selections into reality.
A significant step, yes, but a very small one: about 0.00005 inches in fact. Researchers at Karlsruhe Institute of Technology in Germany say they have rendered (almost) invisible a bump in a layer of gold measuring 0.00004 inches high by 0.00005 inches across, by “cloaking” it in a new material.
The “cloak” is a structure of crystals with air spaces in between, almost like a pile of logs, which is able to bend light. When placed over a small layer of gold, the tiny bump could not be detected at infrared frequencies – very near to the spectrum of light visible to humans.