This year we have had two MSci students working in the group for their final year projects. Chris Richards used Mie scattering theory to calculate optical forces experiences by microscopic particles in optical trapping experiments. In particular he was interested in finding the range of parameters for which an optical pulling force or 'tractor beam' was possible. By finding the fields scattered by a dielectric sphere and evaluating the Maxwell Stress Tensor to find the distribution of optical stress over a sphere he was able to determine the combination of beam and particle properties that would lead to the strongest 'backward' directed scattering force. Above you can see some of Chris' calculated stress distributions on the sphere surface in the forward- and backward scattering directions.
Zhi Hao Wong also worked with us to investigate the optical properties of metallic nanoparticles. Opposite you can see the calculated extinction spectra for gold and silver spherical nanoparticles as a function of size and optical wavelength which clearly show the enhancement of optical scattering arising from their plasmonic properties. Zhi Hao then went on to investigate how these properties could be used to control the dynamics of metallic nanoparticles in optical fields.
More MSci projects will be available for Physics and Natural Science students in the year 2013-14. Contact Dr Phil Jones for details of available projects.