March 8, 2010
Seeing Through Opaque Materials
Physicists find a way to see through paint, paper, and other opaque materials
Materials such as paper, paint, and biological tissue are opaque because the light that passes through them is scattered in complicated and seemingly random ways. A new experiment conducted by researchers at the City of Paris Industrial Physics and Chemistry Higher Educational Institution (ESPCI) has shown that it's possible to focus light through opaque materials and detect objects hidden behind them, provided you know enough about the material. The experiment is reported in the current issue of Physical Review Letters, and is the subject of Viewpoint in APS Physics (physics.aps.org) by Elbert van Putten and Allard Moskof the University of Twente.
In effect, the experiment shows that an opaque material could serve as a high quality optical element comparable to a conventional lens, once a sufficiently detailed transmission matrix is constructed. In addition to allowing us to peer through paper or paint, and into cells, the technique opens up the possibility that opaque materials might be good optical elements in nano-scale devices, at levels where the construction of transparent lenses and other components is particularly challenging.
Image Caption: Knowing enough about the way light is scattered through materials would allow physicists to see through opaque substances, such as the sugar cube on the right. In addition, physicists could use information characterizing an opaque material to put it to work as a high quality optical component, comparable to the glass lens show on the left. Credit: American Physical Society
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