REACTIVE PLASMONICS: OPTICAL CONTROL OF ELECTRONIC PROCESSES AT INTERFACES FOR NANOSCALE PHYSICS, CHEMISTRY AND METROLOGY

The coherent oscillations of mobile charge carriers near the surface of good conductors-surface plasmons- have amazing properties. Light can be coupled to these surface plasmons and trapped by them near the interface between a metal and an adjacent material. This leads to the nanoscale confinement of light, impossible by any other means, and a related electromagnetic field enhancement. The associated effects and applications include high sensitivity to the refractive index of surroundings used in biosensors, enhancement of Raman scattering near the metal surfaces used in chemical sensing and detection, enhanced nonlinear optical effects, localised light sources for imaging, and many others. At the same time the influence of the electrons which participate in the formation of surface plasmons on the surroundings of the metal nanostructures is virtually unexplored. Microscopic electron dynamic effects associated with surface plasmons are capable of significantly influencing physical and chemical processes near the metal surface, not (only) as a result of the high electric fields, but also from the transfer of energetic electrons to the adjacent molecules or materials. We propose to develop a comprehensive research programme in order to understand the physics and harness applications associated with such electronic processes, induced by plasmonic excitations, in designer nanostructures. This will open up new paradigms in ultrafast control over nanoscale chemical reactions switchable with light, optically controlled catalysis, optical and electric processes in semiconductor devices induced by plasmonic hot-electrons, as well as nanoscale and ultrafast temperature control, and many other technologies of tomorrow.

Photonics and nanophotonics are the key enabling technology in many fields and applications and their role in the future is only expected to rise, providing novel disruptive solutions needed for photonics industry growth, as emphasized in the EC H2020 workprogramme, the Photonics21 report: Towards 2020-Photonics driving economic growth in Europe, and the US National Academies document: Photonics-Essential Technology for our Nation. It produces economic and social impact, both directly, as well as through the leverage effect on photonics-enabled applications and markets. The leverage of photonics (defined as the combined contributions photonics makes to the value of services or end products, by enhancing the product functionality or the productivity of the manufacturing process) generated by the European photonics market is worth Euro 58.5billion (21% of the world market) and the European photonics industry employs 290,000 people, with impact on 10% of the EU economy. The UK's Photonic Leadership Group (PLG) report (2013) estimates photonics to be worth £10.5 billion to the domestic economy and to employ some 70,000 people. The proposed programme represents UK-led interdisciplinary research of visionary concepts and disruptive approaches with the aim of unlocking the capacity of plasmonic nanostructures for enhancing functionality of nanophotonic, opto-electronic, biophotonic and photochemical applications that go beyond the limits of current technologies. The proposed workprogramme has the potential to contribute to four of the Great Technologies designated by BIS, namely, big data and energy-efficient computing (by developing nanoscale optical information processing), advanced materials and nanotechnology (by developing new photonic properties arising from nanoscale hybrid structures and photochemistry), energy and its storage (in providing new approaches for photocatalysis and water splitting), quantum technologies (in developing new approaches for the interrogation of single molecules and new nanoscale detectors and light sources).

Particular fields of impact we want to highlight are information technology; energy production, conversion and storage; medical diagnostics and treatment; chemical technologies, overlapping the three Grand Challenges (Energy, Health, and Environment) set by the EPSRC with significant impact on Advanced Materials area. While recent progress in nanotechnology is stimulated by our ability to fabricate and characterize nanoscale systems, the development of so-called 'active' nanoscale devices is still in its infancy. Further growth in this area will require scientists to gain a better understanding of the transient physico-chemical properties of matter and fields at the nanoscale and in ways to controllably tailor these properties artificially, and to enhance the research capacity, knowledge and skills of the private sector: the focus of this research project.