Seeing through opaque materials

But a new experiment conducted by researchers at the City of Paris Industrial Physics and Chemistry Higher Educational Institution (ESPCI) has shown that it is possible to focus light through opaque materials and detect objects hidden behind them, provided enough is known about the material.

To demonstrate their approach to characterise opaque substances, the researchers first passed light through a layer of zinc oxide, which is a common component of white paints. By studying the way the light beam changed as it encountered the material, they were able to produce a numerical model called a transmission matrix, which describes the way that the zinc-oxide layer affected light.

They could then use the matrix to tailor a beam of light specifically to pass through the layer and focus on the other side. Alternatively, they could measure the light emerging from the opaque material and use the matrix to assemble of an image of an object behind it.