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Research Fellows Directory

William Barnes

Professor William Barnes

Research Fellow


University of Exeter

Research summary

I Light is central to our world, providing the energy that supports life, allowing us to communicate fantastic amounts of information around the world, we even use it to analyze the structure of the Universe. We live in an exciting era, one in which many aspects of physics, chemistry, biology and engineering are converging at the molecular or nanoscale, 1-100nm. (A nanometre is one millionth of a mm, roughly the size of 10 atoms in a chain!).

Whilst our ability to make such small structures is progressing well, controlling light on such length scales is a major challenge. Traditionally light can only be manipulated at sizes down to the wavelength of the light involved, typically a few hundreds of nanometres. My research builds on new developments that use metals to control light down at these very small length scales, so providing optical access to the molecular and nano-worlds.

When a church bell is struck the bell resonates and produces sound, the pitch depending on the shape and structure of the bell. In a similar way, when light strikes a small metal particle the electrons in the metal are forced into motion and they too resonate, scattering the incident light. Amazingly, although only ~1000 atoms across, the resonant modes of these very small metallic nanoparticles make them bright enough to be seen individually by eye using an optical microscope. On resonance the light is tightly bound to the particle, being confined to dimensions that may be less than 10 nm, allowing us to harness light at the nanoscale. Despite much recent activity there is still a great deal we do not know.

My research concentrates on exploring the physics underlying plasmonics at the sub-wavelength scale, especially the interaction between light, molecules and nano structured metals. Understanding such interactions will allow us to develop new ways to control light and will be part of wider developments in disciplines as varied as materials and biology.

Grants awarded

Scheme: Wolfson Research Merit Awards

Dates: Oct 2004 - Mar 2010

Value: £150,000