Researchers at the Lawrence Berkeley National Laboratory
Design Microscopic Invisibility Cloak
“It’s an invisibility cloak,” said Ron, a look of awe on his face. “I’m sure it is – try it on.”
Harry threw the cloak around his shoulders and Ron gave a yell.
“It is! Look down!”
Harry looked down at his feet, but they were gone. He dashed to the mirror. Sure enough, his reflection looked back at him, just his head suspended in midair, his body completely invisible. He pulled the cloak over his head and his reflection vanished completely.
– J.K. Rowling, Harry Potter and the Sorcerer’s Stone, page 201
Think of a time in your life when you found yourself in an embarrassing situation. Maybe you fell down the stairs in front of your crush in middle school or went on a blind date with a guy who owns a pet rock collection. Maybe your parents walked in on you making out with your boy/girlfriend or you hit “Reply All” instead of simply “Reply,” sharing a humiliating email with the entire office. In times like these, you simply wish you could disappear.
The good news is, now you can! Though invisibility cloaks come standard in every copy of Harry Potter or season of Star Trek, they have now entered the Muggle world as well. Researchers at the Department of Energy’s (DOE) Lawrence Berkeley National Laboratory have designed a working invisibility cloak. In an article recently published in Science, the scientists explain how they were able to create an ultrathin “skin” that can conform to the shape of any object and conceal it from visible light.
The process is incredibly technical but I have broken it down for you here. When light hits an object, it is scattered outwards in all directions. Our eyes are able to detect this scattering and our brains use this information to fill in the size, shape, and color of the object. Therefore, in order to hide something, you must prevent any light from reaching that object. This is only possible by utilizing metamaterials – materials designed to have properties not found in nature. Their properties are derived not from their base components, but instead how those components have been designed to link together, such as size, shape and orientation.
In this case, researchers fashioned gold nanoantennas, a newly designed metamaterial, into a “skin” merely 80 nanometers thick. For comparison, a human hair is approximately 80,000 – 100,000 nanometers wide! This “nano-skin” was engineered to guide the rays of light around the object like a rock in a stream, thus making it invisible. Depending upon which way the nanoantennas are aligned, the “nano-skin” can be turned on or off.
The Berkeley team has designed invisibility cloaks before, but they were bulky and nearly impossible to scale up to a practical size. The current model is thin and lightweight; it can easily be scaled from its current microscopic state to a macroscopic invisibility cloak. Though still in the early stages, the researchers are optimistic that their find could be used in creating ultra-fast super computers or to enhance cloaking technology on military aircraft. Maybe we’ll even get our very own Harry Potter-inspired fashion line of invisible clothing!
A video showing the cloak in action can be found here.
Original Journal Article: Xingjie Ni, Zi Jing Wong, Michael Mrejen, Yuan Wang, Xiang Zhang. An ultrathin invisibility skin cloak for visible light. Science, 2015 DOI:10.1126/science.aac9411