How to see through opaque materials

March 8, 2010
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

New experiments show that it's possible to focus light through opaque materials and detect objects hidden behind them, provided you know enough about the material.

Materials such as paper, paint, and are opaque because the 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 , and is the subject of Viewpoint in APS Physics by Elbert van Putten and Allard Moskof the University of Twente.

In order to demonstrate their approach to characterize 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 changed as it encountered the material, they were able to produce a called a transmission matrix, which included over 65,000 numbers describing the way that the 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 light emerging from the opaque material, and use the matrix to assemble of an image of an object behind it.

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.

Explore further: Optical vortex could look directly at extrasolar planets

More information: Measuring the Transmission Matrix in Optics: An Approach to the Study and Control of Light Propagation in Disordered Media, S. M. Popoff, G. Lerosey, R. Carminati, M. Fink, A. C. Boccara, and S. Gigan, Phys. Rev. Lett. 104, 100601 (2010) - Published March 08, 2010, Download PDF (free)

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not rated yet Mar 08, 2010
If it's possible to reconstruct sharp image from blurred copy, and in thick layers every dispersion leads to approximately same result, I'd expect, it should be possible to reconstruct image even without knowledge of exact transmission matrix.

Mar 08, 2010
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5 / 5 (2) Mar 08, 2010
Now we'll never know where the security cameras are.
5 / 5 (2) Mar 09, 2010
My guess is that this will only work with very thin, very simple materials. The matrix will get enormous with more complex or thicker materials.
3 / 5 (2) Mar 09, 2010
It also shows potential in millennia old stories about differing materials, crystals, how they are used as energetic focusing and/or resonating devices for 'unseen energies'. What kind? Look up Nikolai Kozyrev's 'superluminal waves'. He found waves that are emanating from massive stellar (and similar) objects which penetrate anything and everything..but are 'time invariant', ie, instantaneous by any known measurement.

Only aluminum, he found, blocks it. He tried the entire table of elements. This means you have your organized and penetrating wave..and then your other materials for focusing and modification. Suddenly and finally... the crystal stuff of the 'new agers' takes on some form of sense.

Remember the fundamental purpose of science. Science is to 'define the unknown', it is not dogmatism to 'reject the unwanted'. A very important and fundamental distinction which some of us need to remember, in a universe where we understand only a few percent of all that is out there.
5 / 5 (1) Mar 09, 2010
Remember the fundamental purpose of science. Science is to 'define the unknown', it is not dogmatism to 'reject the unwanted'.

I respectfully disagree. Science is a method that permits us to understand the physical world as we know it and make testable predictions. It has absolutely nothing to say about the "unknown". That's the purview of religion, mythology and pseudoscience.
not rated yet Mar 09, 2010
Provided your science has no political, religious or financial implications.

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