London, May 4 (IANS): A group of German researchers has developed a Harry Potter-type portable invisibility cloak that can effectively shield objects while being small enough to use in classrooms.

The cloak works using diffused scattered light and like frosted window panes, it lets light in but hides the source of light.

By scattering light, the material slows down the propagation speed of light waves through the medium.

The light can then be sped up to make up for the longer path length around the hidden object.

"Our cloak takes advantage of the much lower effective propagation speed in light-scattering media," said Robert Schittny, from Germany's Karlsruhe Institute of Technology, who led the project.

The cloak cannot hide a human, but it can make small objects disappear from sight.

In the cloak, the object to be concealed is placed inside a hollow metal cylinder coated with acrylic paint, Daily Mail reported.

The tube is embedded within a block of polydimethylsiloxane, a commonly used organic polymer, doped with titanium dioxide nano-particles that make it scatter light.

If the time light takes to travel through the polydimethylsiloxane block is proportionate to the time it takes to travel through the cloak, the core will become invisible.