The evaluation committee believes that throughout the course of his PhD, Verhagen has carried out an impressive number of experiments that are theoretically well supported. By doing this, he has developed into a highly versatile researcher. "He is capable of taking a step back and placing his research in context with respect to both the scientific discipline and possible applications", wrote the jury. According to the committee, the thesis has an "exceptional clarity" and a "strong theoretical basis and analysis". They therefore conclude that Verhagen is a worthy winner of this new FOM Prize.
Ewold Verhagen (1980) gained his doctorate cum laude on 16 December 2009 from Utrecht University. He carried out his research at the FOM institute AMOLF, under the supervision of Prof. A. Polman and Prof. L. Kuipers. The research led to no less than twelve publications, including three in Nano Letters and two in Physical Review Letters. Verhagen is currently working as a postdoc at the Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland.
For his research, Verhagen manipulated the behaviour of light using metal nanostructures. A metal surface can conduct light in the form of 'plasmons', a certain type of electromagnetic waves. Verhagen investigated new ways of controlling the properties of these plasmons so that the light could be confined at the nanometre scale. He showed that the wavelength in various wave conductors can be considerably shorter than those of light. He also theoretically demonstrated that the diffraction index in such wave conductors can be negative. Based on these findings, he designed a three-dimensional material in which light waves ‘move backwards’ so to speak; towards a light source instead of away from it. By making use of narrowing wave conductors, sort of gold funnels, he was able to efficiently concentrate the electromagnetic radiation on longitudinal scales that were many times smaller than the wavelength of light in the open. In the future, such control over electromagnetic fields could be used for applications in light sensors and solar cells, for example.
FOM awards various prizes to physics researchers. The FOM Physics Thesis Award will be awarded from this year onwards to the best physics thesis. Selection criteria for the prize are: new insights obtained through the research, originality of the research method, scientific breadth and depth demonstrated by the candidate and presentation of the research in the thesis.
About the research: Ewold Verhagen, +41 21 693 58 55 (office), +41 21 693 05 59 (lab).
About the prize: Noortje Vis, +31 30 600 12 17.
Ewold Verhagen's thesis is also available online.