January 13, 2015
New invisibility cloak could help surgeons, drivers
Chuck Bednar for redOrbit.com - Your Universe Online
Attempts to build a Harry Potter-style cloak of invisibility have come and gone, but the inventors of The Rochester Cloak continue to hone their craft, and this week released new video footage of what they are calling the world’s first known 3D continuous multidirectional cloaking device.The device, which we first reported on back in September, was created by the team of University of Rochester physics professor John Howell and graduate student Joseph Choi and uses ordinary lenses to obscure objects from sight at a variety of different angles. It works by bending light and sending it through four lenses, which can keep objects hidden at multiple points of view.
In the new video, the university explained that the device could be used by surgeons to see through their hands while operating on a patient, or by drivers to help detect cars in their blind spots while behind the wheel. While the unit is called The Rochester Cloak, it actually looks more like the type of equipment you would expect to see in an optometrist’s office.
Choi spoke with MTV News about the device earlier this month, and explained that it was “very simple... it’s a little more than just putting a few magnifying glasses together.” He added that he and Howell were “surprised that people thought this was really cool,” and that they were waiting “for the patent application to come out” before going public with their invention.
In November, the duo published a paper detailing their work in the journal Optics Express, and explained that their technique uses “ray optics, albeit with some edge effects” and requires “no new materials,” utilizes “isotropic off-the-shelf optics” and is able to scale so that it can “easily... cloak arbitrarily large objects” and “is as broadband as the choice of optical material.”
All of those attributes, they wrote, “have been challenges for current cloaking schemes.” Their take on the invisibility cloak is also less complicated and less expensive than other such efforts. In September, the duo said that they used just over $1,000 worth of materials to build their unit, and that they believed that it could be accomplished even less expensively.
Furthermore, kits inspired by Howell and Choi’s work can be ordered online for just $49. Those kits include six cemented doublet achromats 33 millimeters in diameter and a mini optical bench to set they up with. Of course, the kit also comes with instructions, including details on the specific distances to separate each of the lenses and other information relevant to the project.
While the Rochester researchers have previously called their cloaking device an improvement over other efforts, they acknowledged that it is not perfect. Choi said that, since it bends light and sends it though the device’s center, the on-axis region cannot be cloaked or blocked. In short, the cloaked region is essentially limited to a doughnut-shaped region.
Choi told MTV News that he and Howell are currently working on a few new patents for devices that have larger lenses, which could even cloak a larger area than is currently possible. Also, they are looking at the use of plastics in a version of the device, which would further reduce the cost.