Skip to main content

Frontiers in Surface Plasmon Photonics - Fundamentals and Applications

Final Report Summary - PLASMONICS (Frontiers in Surface Plasmon Photonics - Fundamentals and Applications)

In this project called “Plasmonics” we were interested in the interactions of light, metal and molecules. Light can be trapped at the surface of metals and this property can be used to create improved optical devices and miniature optical circuits which constituted one part of the project. This is important, for instance, in the context of the ever increasing electric energy consumption by the web, a serious environmental problem for which one solution would be to replace part of the present electrical circuits by such optical devices. In another part of this project, we explored how the presence of molecules would modify the properties of surface plasmons, the scientific term for the light trapped at the metal surface. This has already been used over the past 30 years for biomedical sensing of minute quantities of enzymes, proteins, etc. and we aimed to overcome some limitations. At the same time, we explored how the properties of the molecular materials could be modified by having them strongly interact with electromagnetic waves such as surface plasmons. This could pave the way for new science and technology as we demonstrated. Below are some examples of specific achievements of this project.
Structuring a metal at the scale of the wavelength of light can be used to create miniature optical devices that modify the properties of a light beam as it interacts with the metal. The figure on the left illustrates this idea. Spiral are engraved around a tiny hole in a thin metal film. When light impinges on the metal surface, it is momentarily trapped there and as it escapes the surface, it has acquired a twist, spinning through space as it travels. This spinning can be recorded as shown in the right panel. This could be used in optical communication platforms.
Electromagnetic vacuum fluctuations are omnipresent in our universe and they are known to influence many events in our environment. Molecules can be made to interact very strongly with such fluctuations if placed in metallic structures that will resonate with both the molecules and the fluctuations. The interaction can be so strong that the properties of the molecules are significantly modified. For instance the colour of the molecules interacting with the fluctuations can be changed. In the course of this project we demonstrated for the first time that vacuum fluctuations can be harvested to modify the rate and yield of a chemical reaction and to improve the conductivity of organic semiconductors, among other things. These proofs of concept will no doubt have important consequences for molecular and material science and the related technologies, stimulating new R&D to explore the full potential of this approach to modify material properties.
* Please, notice that this summary will be published