Confinement of photons, electrons and magnetism in nano/meta-materials
Lead Research Organisation:
University of Bath
Department Name: Physics
Abstract
This PhD project studies the linear and nonlinear (colour-changing) optical properties of nanoparticles and artificially nanostructured materials and surfaces.
Nanostructuring materials and surfaces (creating an artificial structure, e.g. an array of geometrical shapes, on the nanoscale) strongly affects their optical properties. Thus, it is possible to design and manufacture nanosurfaces with desired properties for specific applications. Often, the nanosurfaces are made of plasmonic metals. These metals (e.g. gold, silver, aluminium, ...) host plasmons (coherent oscillations of electrons on the surface of these metals) and interact strongly with light.
Plasmonic nanoparticles can be used to study new optical phenomena, such as optical activity in hyper-Rayleigh scattering. In hyper-Rayleigh scattering, light scattered from the nanoparticles has double the frequency of the incident light (e.g. if red light is incident on the nanoparticles, the scattered light is blue). Optical activity means that the amount of scattered light depends on the circular polarisation ("twist") of the incident light. The effect has potential use in sensitive characterisation of molecules used in pharmaceuticals. In this project, we study hyper-Rayleigh scattering in suspensions of plasmonic nanoparticles with various geometries to gain better understanding of the effect, which is essential for successful future applications. The project might involve attaching chemical molecules to plasmonic nanoparticles with the aim of increasing their optical response.
Plasmonic nanosurfaces studied as part of this project have potential applications in increasing the accuracy of optical characterisation of molecules, in detecting air pollution and in other areas. The aim of our research is to characterise and optimise the performance of these structures.
We also plan to design nanosurfaces made of magnetic materials with the aim of tuning the optical properties of the nanostructures with magnetic field.
Mostly optical methods are used to study the nanoparticles and nanostructures. These include well-established methods, such as optical microscopy, as well as novel optical experiments, which we assemble in our lab. The exact experimental configuration depends on the studied samples but, generally, we use ultrashort-pulse lasers as light sources and design our experiments in a way to maximise the sensitivity of detection of the nonlinear properties of the samples.
Nanostructuring materials and surfaces (creating an artificial structure, e.g. an array of geometrical shapes, on the nanoscale) strongly affects their optical properties. Thus, it is possible to design and manufacture nanosurfaces with desired properties for specific applications. Often, the nanosurfaces are made of plasmonic metals. These metals (e.g. gold, silver, aluminium, ...) host plasmons (coherent oscillations of electrons on the surface of these metals) and interact strongly with light.
Plasmonic nanoparticles can be used to study new optical phenomena, such as optical activity in hyper-Rayleigh scattering. In hyper-Rayleigh scattering, light scattered from the nanoparticles has double the frequency of the incident light (e.g. if red light is incident on the nanoparticles, the scattered light is blue). Optical activity means that the amount of scattered light depends on the circular polarisation ("twist") of the incident light. The effect has potential use in sensitive characterisation of molecules used in pharmaceuticals. In this project, we study hyper-Rayleigh scattering in suspensions of plasmonic nanoparticles with various geometries to gain better understanding of the effect, which is essential for successful future applications. The project might involve attaching chemical molecules to plasmonic nanoparticles with the aim of increasing their optical response.
Plasmonic nanosurfaces studied as part of this project have potential applications in increasing the accuracy of optical characterisation of molecules, in detecting air pollution and in other areas. The aim of our research is to characterise and optimise the performance of these structures.
We also plan to design nanosurfaces made of magnetic materials with the aim of tuning the optical properties of the nanostructures with magnetic field.
Mostly optical methods are used to study the nanoparticles and nanostructures. These include well-established methods, such as optical microscopy, as well as novel optical experiments, which we assemble in our lab. The exact experimental configuration depends on the studied samples but, generally, we use ultrashort-pulse lasers as light sources and design our experiments in a way to maximise the sensitivity of detection of the nonlinear properties of the samples.
Planned Impact
The Institute of Physics has estimated that physics-dependent businesses directly contribute 8.5% to the UK's economic output, employ more than a million people and generated exports amounting to more than £100bn in 2009. They go on to say: "It is important for businesses to have access to a range of highly skilled (and motivated) individuals capable of thinking 'outside of the box', particularly physics-trained postgraduates due to the highly numerate, analytical and problemsolving skills that are acquired during their training." If funded, the graduates of this CDT will have such skills and motivation. We would hope that this would significantly contribute towards satisfying the UK's need for trained scientists, particularly in the field of condensed matter physics. The impact would go further than this. By working more closely with industry and other partner organisations, we would reshape the conventional PhD programme to improve the experience for all.
In addition to the training aspect of the CDT there would be an important research impact. The Universities of Bristol and Bath have many world-leading researchers across the condensed matter field. By working with the high-quality students that we hope to recruit into the programme we will produce significant cutting edge research in condensed matter. The research would bear on some of the grand challenges facing condensed matter physics such as: understanding the emergence of new phenomena far from equilibrium; the nanoscale design of functional materials such as graphene; and harnessing quantum Physics for new technologies. Ultimately, this would contribute to improvements in many technologies, for example, energy or data storage technology.
In addition to the training aspect of the CDT there would be an important research impact. The Universities of Bristol and Bath have many world-leading researchers across the condensed matter field. By working with the high-quality students that we hope to recruit into the programme we will produce significant cutting edge research in condensed matter. The research would bear on some of the grand challenges facing condensed matter physics such as: understanding the emergence of new phenomena far from equilibrium; the nanoscale design of functional materials such as graphene; and harnessing quantum Physics for new technologies. Ultimately, this would contribute to improvements in many technologies, for example, energy or data storage technology.
