Researchers have trapped a rainbow - slowing light to a near-stop - in an array of 25,000 "invisibility cloaks", each smaller than a hair's breadth. A report in the New Journal of Physics shows how the quest for an invisibility cloak is leading to cleverer ways to use and manipulate light. The trick could aid the analysis of complex samples or even communications. Read more
'Cloaking' a 3-D object from all angles demonstrated
Researchers have "cloaked" a three-dimensional object, making it invisible from all angles, for the first time. However, the demonstration works only for waves in the microwave region of the electromagnetic spectrum. Read more
Active invisibility cloaks University of Utah mathematicians developed a new cloaking method, and it's unlikely to lead to invisibility cloaks like those used by Harry Potter or Romulan spaceships in "Star Trek." Instead, the new method someday might shield submarines from sonar, planes from radar, buildings from earthquakes, and oil rigs and coastal structures from tsunamis.
"We have shown that it is numerically possible to cloak objects of any shape that lie outside the cloaking devices, not just from single-frequency waves, but from actual pulses generated by a multi-frequency source" - Graeme Milton, senior author of the research and a distinguished professor of mathematics at the University of Utah.
Scientists have rendered objects invisible to near-infrared light. Unlike previous such "cloaks", the new work does not employ metals, which introduce losses of light and result in imperfect cloaking. Because the approach can be scaled down further in size, researchers say this is a major step towards a cloak that would work for visible light.
Researchers at Duke University, who developed a material that can "cloak" an item from detection by microwaves, report that they have expanded the number of wavelengths they can block. In 2006 the team reported they had developed so-called metamaterials that could deflect microwaves around a three-dimensional object, essentially making it invisible to the waves. The system works like a mirage, where heat causes the bending of light rays and cloaks the road ahead behind an image of the sky.