It’s official—the invisibility cloak is no longer just another product of childhood fantasy or J. K. Rowling novels. We’ve been waiting for this day for ages and had been ready to give up hope altogether until we stumbled upon this "transparent cloak" from a research team at the University of Tokyo's Tachi Lab. Led by Dr. Susumu Tachi (who’s currently at Keio University), researchers have been developing this concept since 2003, and if the above video is any indication, they’ve made some impressive strides.
OK, so we have to confess—in actuality the cloak isn’t really see-through. It simply creates the illusion of transparency through a meta-material technology called Retro-reflective Projection Technology (RPT). The cloak is made from a material composed of tiny glass beads that reflect light only in the direction it comes from, rather than refracting light in various directions like a television screen or similar.
According to the diagram above, the cloak has an embedded camera in the back that captures the scene behind the wearer. A computer processes the background imagery and relays it to a projector that filters through a half mirror and projects the scene onto the wearer. From a certain angle, the cloaked person looks transparent to onlookers.
The concept has been put to use in cars, eliminating neck craning by aiding drivers who are driving in reverse. Tachi suggests the technology could be embedded into car doors to help counteract blind spots, or in the floors of planes so pilots can land on the ground more safely. Tachi also imagines all kinds of implications for augmented reality, perhaps even embedding the material in eyeglasses and other, similar screen-like interfaces.
It may yet be a while before a true invisibility cloak hits the market but this new prototype has certainly reignited our enthusiasm and imaginations. In the meantime, we’ll just be dreaming of the day when RPT becomes ready-to-wear.