Current Research Topics
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Advanced Materials for Nanophotonics
Materials with unique dielectric and plasmonic properties offer new and enhanced modes of light-matter interaction. They are redefining the limits of what is possible in terms of the magnitude and speed of material response to optical excitation over nanometre-scale interaction lengths, and promise step-changes in the miniaturization and reduced energy consumption of optical modulation, sensing, switching and memory devices. We are investigating nonlinear and phase-change response mechanisms in a variety of ultra-thin and nanostructured designer optical materials, including extremely high-/low-refractive index dielectrics, and plasmonic ‘topological insulators’ with intriguing electromagnetic surface states.
"Compositionally controlled plasmonics in amorphous semiconductor metasurfaces"
Opt. Express (2018)
"Phase-change-driven dielectric-plasmonic transitions in chalcogenide metasurfaces"
NPG Asia Mater. (2018)
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Metamaterials and Telecoms
We are developing approaches to the integration of metamaterial-enabled devices with optical fibre telecommunications technology. In particular we are investigating and seeking to demonstrate ways in which metamaterials can help to guide and control light signals in optical fibres, by engaging a variety of phenomena such as structural phase transitions in nanostructured and confined solids, nano-mechanical motion, or nonlinear and coherent light-matter interactions.
"Fibre-optic metadevice for all-optical signal modulation based on coherent absorption"
Nat. Commun. (2018)
“Controlling the optical response of 2d matter in standing waves”
ACS Photon. (2017)
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Free Electrons and Photonic Nanostructures
When free-electrons fly past or impact on nanostructures, they generate light. These interactions can be used to create new types of tuneable nanoscale light sources. Moreover, the light emitted can provide detailed information about the nanostructure itself. Using free electrons we are developing novel nanoscale optical sources, studying nanostructures with an unprecedented combination of spatial and temporal resolution, and investigating how advanced dielectric and plasmonic material platforms and nanostructures can provide novel free-electron functionalities for photonics at the nanoscale.
"Holographic free-electron light source"
Nat. Commun. (2016)
"Amplification of the Evanescent Field of Free Electrons"
ACS Photonics (2015)
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Nano-opto-mechanics
We are developing metamaterials consisting of nanoscale building blocks that can be moved by forces arising, for example, from the application of electrical and magnetic signals or optical illumination. This controlled nanoscale motion can rapidly and radically (but reversibly) change the optical properties of materials. We are investigating the intriguing physics of electromagnetic, elastic and optical forces at the nanoscale, aiming to develop practical applications of nano-opto-mechanical metamaterials in photonic devices.
"Giant electro-optical effect through electrostriction in a nano-mechanical metamaterial"
Adv. Mater. (2019)
"Reconfigurable nanomechanical photonic metamaterials"
Nature Nanotech. (2016)
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Toroidal Electrodynamics
We are investigating the unique properties of toroidal excitations in matter and developing a new type of optical spectroscopy sensitive to toroidal transitions. This will provide a unique new tool to probe the physics of interactions and energy/information transfer involving toroidal excitations at the molecular and macro-molecular level in novel artificially structured media and biologically important systems.
"Pulse generation scheme for flying electromagnetic doughnuts"
Phys. Rev. B (2018)
"Electromagnetic toroidal excitations in matter and free space"
Nature Mater. (2016)
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Computational Nanophotonics
We are developing a platform for multiphysics modelling of the nonlinear properties of plasmonic nanostructures at a range of different length scales. Our approach employs a combination of finite element methods, discrete dipole approximations and semi-analytical considerations based on the multipole expansion. We consider the coupling of electronic, magnetic, and thermal properties of materials to the plasmonic response in nanostructures, aiming to design metamaterials with novel functionalities.
"Light emission by accelerated electric, toroidal, and anapole dipolar sources"
Phys. Rev. A (2018)
"Many-Body subradiant excitations in metamaterial arrays: experiment and theory"
Phys. Rev. Lett. (2017)