| THz materials, imaging and spectroscopy; Nonlinear optics We explore the potential for developing new THz components and sensors to fill the so called “THz gap”, utilizing novel magnetic and plasmonic responses of many materials in this region, and are currently working on novel methods for imaging in this difficult spectral region. We also work in plasmoncs, and explore the possibility of replacing coinage metals with new materials such as graphene and ITO. These materials have tuneable electromagnetic responses, as free electrons can controllably introduced by chemical, electrical or photo- doping, making the manipulating light on extreme sub-wavelength length scales possible, and we focus on enhancing nonlinear optical responses for optical switching etc. Group page |
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| Theory of electromagnetic and acoustic materials Design of electromagnetic materials: Suppose you want to do something to a wave; perhaps redirect a radio wave, or absorb a sound wave. I use mathematics to look for the materials you need. I am interested in the theory of electromagnetism and wave physics in general. Recently I've been thinking about how waves reflect from metamaterial structures, but I also work on the theory of quantum electromagnetism in dielectric media (I am interested in understanding how macroscopic bodies affect the quantum properties of the electromagnetic field, and how these in turn affect the motion of the object). Group page |
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| Quantum Nanophotonics Optoelectronic devices, which generate, manipulate and measure light, underpin modern communication and have enabled the internet to revolutionise the modern world. A new generation of quantum optoelectronic devices, which process light at the single photon level promise a further revolution in the way we communicate, measure and process data. Individual photons, the elementary particles of light, are the building blocks of this technology, but must first be generated by single photon sources. For practical applications the photons must be generated on-demand, at high repetition rates and must be indistinguishable, in other words identical in all degrees of freedom (for example energy and polarisation). My research is centred around the development of such devices through the exploration of novel materials and their nanophotonic integration. Group page |
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| Magnonics We study phenomena associated with spin waves (elementary excitations of the magnetic order) and magnons (their quanta). Spin waves carry energy and angular momentum via a collective wave motion of spins. So, the relation between magnonics and the rest of spin physics (aka spintronics) is akin that between the ac and dc electricity. Magnonics offers the perspective of technology that would use spin waves (or magnons) to carry and process both analog signals and digital data. The most attractive features of this technology are the low power, magnetic reconfigurability and scalability to nanometre dimensions. Group page |
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| Biophotonics and Biomechanics The mechanical properties of biological tissues are central to their function and impairment is implicated in ageing and disease. Changes in the macroscopic mechanical properties and tissue structure and composition are both well characterised, but the causal relationships between them are largely unclear. A novel microscopy technique based on Brillouin light scattering from acoustic waves at GHz frequencies has emerged for the contactless 3-D probing of tissue mechanics at the microscopic and subcellular levels. In Exeter we advance the development and applications of Brillouin microscopy as a novel optical technique within biophotonics and the clinical environment. Key word: THz Raman spectroscopy Group page |
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| Structured light I work with Prof Hendry on compressive sensing techniques to speed up Terahertz imaging. Group page Biomedical Physics |
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| Active/Reconfigurable Metasurfaces; phase-change materials Conventional metamaterials and metasurfaces (the 2D form of metamaterials) are ‘fixed-by-design’, with performance determined by the form of their resonating structures and the properties of the materials of which they are made. Far greater functionality and application would be available if we could develop active versions, i.e. metamaterials whose response can be dynamically adapted, tuned or reconfigured. At Exeter we are doing just this, using chalcogenide phase-change materials to deliver active optical metasurfaces that can work from the UV right out to the THz, and with applications ranging from LiDAR to multispectral imaging, optoelectronic displays, chemical sensing and much more. Group page |
