Light’s speed slows in plywood, clouds, bones and other composite materials, but measuring by how much it slows has been a difficult task. Now scientists have found a way to determine the speed of light in such a material by varying its pressure, according to a report to appear in an upcoming Physical Review Letters.
“It’s a very compelling and exciting piece of work,” says physicist Allard Mosk of the University of Twente in the Netherlands.
The technique could help scientists understand the nature of how light interacts with materials such as paints, foams, filters and human body tissue. And it may lead to applications for testing the quality of pharmaceuticals.