Looking through an opaque material
A team of researchers from the Netherlands and Italy – including FOM workgroup leaders professor Ad Lagendijk, professor Willem Vos and professor Allard Mosk – has succeeded in making sharp pictures of objects hidden behind an opaque screen. This breakthrough in research has been published on 8 November in the world-leading research journal Nature.
FOM research three times in top ten of 2012 breakthroughs
On 14 December the authoritative magazine Physics World announced that the breakthrough of the Year goes 'to the ATLAS and CMS collaborations at CERN for their joint discovery of a Higgs-like particle at the Large Hadron Collider'. A discovery by FOM workgroup leaders professor Allard Mosk, professor Ad Lagendijk and professor Willem Vos of the MESA+ Institute at the University of Twente has been ranked as one of the ten most important breakthroughs in physics research in 2012. The discovery of majorana particles by FOM focus group leader professor Leo Kouwenhoven is also in the top ten.
Materials such as skin, paper and ground glass appear opaque because they scatter light. In such materials light does not move in a straight line, but travels along an unpredictable and erratic path. As a result, it is impossible to get a clear view of objects hidden behind such materials. Powerful methods have been developed to retrieve images through materials in which a small fraction of the light follows a straight path. To date, however, it has not been possible to resolve an image from light that has been completely scattered.
A team from the MESA+ Institute for nanotechnology at the University of Twente in the Netherlands has now succeeded in doing just this. The researchers, led by Allard Mosk, scanned the angle of a laser beam that illuminated an opaque diffuser. At the same time, a computer recorded the amount of fluorescent light that was returned by a tiny object hidden behind the diffuser. Mosk point out that: "While the measured intensity of the light cannot be used to form an image of the object directly, the information needed to do so is in there, but in a scrambled form. The two young scientists who are the first authors of this paper had the brilliant idea to find out whether that scrambled information is sufficient to reconstruct the image – and they found a way to do so." Their method involves a computer program that initially guesses the missing information, and then tests and refines the guess. They succeeded in making an image of a hidden fluorescent object just 50 micrometers across – the size of a typical cell.
The researchers expect their work to lead to new microscopy methods capable of forming razor sharp images in a strongly scattering environment. Allard Mosk notes that: "This will be very useful in nanotechnology. We would like to bring structures to light that are hidden inside a complex environments like computer chips." They also dream of extending their method to examine objects under the human skin. "But for the moment," says Mosk, "our method is too slow for that."
This study was supported by the Netherlands Organization for Scientific Research (NWO), the Foundation for Fundamental Research on Matter (FOM), the Technology Foundation STW, the European Research Council (ERC) and the Italian Ministry of Education, Universities and Research.
Reference
'Non-invasive imaging through opaque scattering layers' Jacopo Bertolotti, Elbert G. van Putten, Christian Blum, Ad Lagendijk, Willem L. Vos and Allard P. Mosk.
The authors work at the Complex Photonic Systems (COPS) research group of the MESA+ Institute for Nanotechnology at the University of Twente in the Netherlands. Jacopo Bertolotti is also affiliated to the University of Florence and Ad Lagendijk is also affiliated to the FOM-institute AMOLF in Amsterdam. Christian Blum is affiliated to the Nanobiophysics (NBP) research group of the MESA+ Institute for Nanotechnology at the University of Twente in the Netherlands. Elbert van Putten and Jacopo Bertolotti contributed equally to this work.
DOI: 10.1038/nature11578
Research in top ten of 2012 breakthroughs
On 14 December the authoritative magazine Physics World announced that the discovery by FOM workgroup leaders professor Allard Mosk, professor Ad Lagendijk and professor Willem Vos of the MESA+ Institute at the University of Twente has been ranked as one of the ten most important breakthroughs in physics research in 2012.
Further details and press material including high-resolution graphics:
Allard P. Mosk