We all know that light goes through transparent materials, like the glass lens of a digital camera, but what we may not be aware of is that light also goes through some materials that seem opaque to our eyes.
Some materials (such as zinc oxide, a common ingredient in white paints) let some light pass but scatter it in chaotic ways so that our naked eyes [and the processing unit up in our brain] do not know how to reassemble that light back into coherent images.
Now, using some clever math, a team of researchers at the City of Paris Industrial Physics and Chemistry Higher Educational Institution (ESPCI) has developed a numerical transmission matrix, studied how light changes upon passing through it, and devised a way to focus light through opaque materials to “see” objects on the other side.
Practical applications are curently focused on seeing through cell walls and other membranes to see what’s happening on the other side.[ via PopSci ]