For those who have read the Harry Potter series, the idea of possessing the Invisibility Cloak in real world is probably the most desired fantasy. There have been many attempts to create cloaking devices in past years that made use of complex and technically intricate methods. However, a team of scientists from the University of Rochester has designed a cloaking device that just uses four lenses.
A cloaking device using four lenses developed by University of Rochester physics professor John Howell and graduate student Joseph Choi. Credits: REUTERS/J. Adam Fenster
The idea behind a cloaking device is quite simple: bend light around the object you wish to cloak. However, the easier the idea, the more difficult is its practical application. The researchers have devised a simple device that can hide small objects using just four magnifying lenses. What is the function of these lenses? They converge the light rays to a single beam and object outside this beam becomes invisible.
“There’ve been many high tech approaches to cloaking and the basic idea behind these is to take light and have it pass around something as if it isn’t there, often using high-tech or exotic materials,” says John Howell, Physics Professor at University of Rochester.
Device Set-up. Credits: rochester.edu
Although there are other cloaking devices as well, this one is first of its kind. While other devices only cloak objects at particular angles, this device cloaks objects in 3 dimensions- no matter which angle you look from, the object remains hidden.
“This is the first device that we know of that can do three-dimensional, continuously multidirectional cloaking, which works for transmitting rays in the visible spectrum,” Says Choi, a PhD scholar at the UoR.
Additionally, other devices also distort the background making it obvious that a cloaking device is being used. Furthermore, these devices are quite expensive and are made from materials that are hard to come by. However, this simple cloaking device also has one teeny-weeny glitch:
“This cloak bends light and sends it through the center of the device, so the on-axis region cannot be blocked or cloaked,” said Choi.
This means that the single beam at the center of the device will make the object apparent. So, keep the objects out of the center to ensure they are hidden. Anyone can set up this device. All you need are four magnifying lenses. Next distance them 20 cm apart and between the last two lenses, move something sideways till you find a place where the beam is smallest – called the “sweet spot”.
Set up. Credits: Nisenet
For detailed instructions, you can take help from this Nisenet document.
This cloaking device by the University of Rochester is cheap, incredibly simple, easy to set-up and pretty effective. Maybe this device could further be improved to even remove that single beam of light. Nevertheless, the experiment is an excellent DIY project that makes an exciting cloaking device.
