New technique for imaging uses scattered light

Ars Technica : Many materials, such as sugar crystals and human skin cells, are transparent when viewed individually or in small quantities. Scattering of light is what turns those materials opaque when viewed in bulk. Jacopo Bertolotti and Elbert van Putten of the University of Twente in the Netherlands and colleagues have found a way to image objects hidden in those types of opaque materials. As a laser passes through the scattering material, the beam of light is redirected and split. The splitting causes the light that comes out the other side to interfere with itself and sometimes end up in phase. When the light is in phase, it creates a bright spot, which reflects off the hidden object. When the researchers change the angle of the light, the bright spot moves predictably. By mapping the bright spot’s reflections and known locations, they can calculate the shape of the object. The technique likely has many uses in research labs, but as yet it can only penetrate a few millimeters into a sample and still make clear images.