MESA+ University of Twente
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Elbert van Putten (promotion date: 28 October 2011)

Disorder-enhanced Imaging with Spatially Controlled Light

Promotion date: 28 October 2011

Promotores: Prof. dr. Ad Lagendijk

Prof. dr. Allard Mosk

In stark contrast with common belief we showed that scattering of light does not have to be detrimental to imaging but can be used to greatly improve the imaging capabilities of lenses.

We developed, together with the FOM Institute AMOLF and the University of Florence, a scattering lens that creates images at a sub-100 nm resolution using visible light; much sharper than even the most expensive conventional lenses are able to create.

At the core of scattering lenses is our ability to manipulate the propagation of scattered light by spatially controlling the wave front before the light impinges onto the lens; a technique developed in our group.

With meticulous control over the scattered light we even managed – for the first time ever- to retrieve an image of an object completely hidden by an opaque layer, without requiring any access to the back of the layer. We believe that the possibility to optically image through opaque materials promises exciting applications in various fields, including biological imaging.

Were there some decisive moments during your thesis project?

In the experiments on our high-resolution scattering lens, I vividly remember the first time we actually succeeded in imaging a small structure with it. Of course, the image was not perfect and a lot still had to be improved, but these kind of intermediate results, time and time again, are vital to affirm oneself you are on the right track.

For example, altogether it took a long period before the lens finally was build; much longer than we anticipated at the start of the project. At a certain point we even found out it could never work, so we had to go back to the drawing and design table to work out new ideas (that were already popping up quite soon). In such cases, intermediate results are important to cherish.

Did your work lead to nice publications?

Very much so. Showing that scattering of light not necessarily leads to loss of resolution - even using this phenomenon to improve it considerably – led to a nice publication in the leading journal Physical Review Letters. Subsequently, this publication received a lot of media attention in, for example, quality national newspapers like NRC Handelsblad, and internationally in top magazines like: Science, Nature Nanotechnology and Wired. Furthermore, we are currently working hard to transform a few other chapters from my thesis into publications.

How did you develop personally as a researcher and scientist?

I learned a great deal of working independently on a complicated issue in which a lot of aspects are involved. Being confronted to these, and finding solutions to the multiple aspects involved, is challenging and rewarding in a way it never occurred to me before. This process is especially rewarding if things work out well at the end.

Furthermore, I learned to be proud of the results achieved and making them known to a wider audience. Writing down the results and the impact of your work in an accessible way sometimes can be very hard. Giving attention to press releases that communicate to the public in the right way nevertheless is inevitable to bring your work to the public. This, in turn, is very important getting the credits you deserve personally and also for the standing of the research group as a whole. And, even more important, I feel that communicating your results to the public is part of the responsibility that a scientist has towards society. After all, we should not forget that society still pays a large part our work.

That being said, I hope our politicians also fully realize the importance science has as a driving force of innovation. Just adding the word ‘top’ to all your investments does not automatically bring your country to the top 5 knowledge economies; it requires real vision, real long term investments, and a policy that does not only focus on applications but also dares to deeply support fundamental research.

What are your future plans?

Working towards applications is a big challenge in my new job at Philips Research. I feel it is time for me to broaden my horizon and take a profound look how research functions in industry. As an engineer by heart, it is very exciting to build products and actualize the functionalities that are promised.

Being part of Mesa+, which aspect do you cherish most?

In the first place I acted as a member of the Complex Photonics Systems group, collaborating in a joined FOM project together with colleague scientists there. In the middle of my PhD MESA+ started the strategic research orientation Applied Nanophotonics (ANP) led by Dr. Pepijn Pinkse. The start of ANP initiated a much closer collaboration between the various optical groups, from which also our research benefitted.

Furthermore, the technicians of MESA+ did some amazing things for us: without them we would never have come to the stunning results we obtained. Especially the materials experts helped us a great deal. Also, having access to the fine deposition techniques at Mesa+ was decisive. The way the experts were open-minded in dealing with my questions and were willing to cooperate, is a strong selling point of MESA+.