Materials such as paper, paint or biological tissues are opaque because the light that passes through them is scattered in complex and seemingly random ways. A new experiment carried out by researchers from the Higher Education Institution of Physics and Industrial Chemistry of the city of Paris (ESPCI) has shown that it is possible to focus light through opaque materials and detect objects hidden behind them , as long as it is know enough about the material. The study has been published in the latest issue of the journal Physical Review Letters .
To do this, the researchers passed light through a layer of zinc oxide, which is a common component of white paints. By studying how the light beam changes as it encounters the material, they were able to produce a numerical model called a transmission matrix, which includes more than 65,000 numbers that describe how the zinc oxide layer affects light. .
Experience showed that an opaque material could serve as a high quality optical element comparable to that of a conventional lens . In addition to looking through paper or paint, and even inside cells, the technique offers the possibility that opaque materials become good optical elements for nano-devices , at levels where the construction of transparent lenses and other components is especially difficult.
