PhD Studentship: Topology-enhanced lanthanide surfaces for luminescence detection

Project Title: Topology-enhanced lanthanide surfaces for luminescence detection

This interdisciplinary project will explore novel designs of plasmonic surfaces based on defined topologies to optimise the plasmonic effect on lanthanide luminescence. Lanthanides have attractive luminescent properties, with a characteristic fingerprint luminescence signal which has long lifetimes and narrow bandwidth. The near infra redemitting lanthanides, Yb, Nd, Er have characteristic profiles which range from 900 nm to 1500 nm. In the project we will design plasmonic surfaces to enhance lanthanide luminescence. Surface modelling will assist for defined topologies using designed lanthanide emitters. These photonic systems will bring a paradigm shift in integrated photonic systems for optical communications and healthcare.

Research background

Interaction of light with interfaces is very important in optics. At an interface, light experiences reflection, refraction at a smooth surface, or scattering and diffraction if the surface is structured. In addition, light can be guided at the interface between two media of certain properties, such as metal and dielectrics. These are some of the most ffundamental optical processes in optics that form the basis for most of the practical optical devices.

Most metasurfaces developed are passive devices that operate on light coming from external light sources. However, it is anticipated that active metasurfaces with integrated light emitters will enable broader applications. Appropriately designed plasmonic metasurfaces provide an attractive platform to attach active emitters and modulate light properties. They can not only enhance the photoluminescience of integrated emitters through the Purcell effect (i.e. increased spontaneous emission due to enhanced optical density of states), but also provide powerful control over the direction and polarization state of the emitted light.

Computational designs are employed to optimise surface structural features to enhance the plasmonic effect. Topological Optimisation (or Inverse Design) is a computational design approach for discovering optical structures based on specified functional characteristics. The technique is currently revolutionising the field of nanophotonics by allowing for the algorithmic design of photonic devices such as filters, couplers, splitters and diplexers.

Lanthanides have attractive luminescent properties, with a characteristic fingerprint luminescence signal which has long lifetimes and narrow bandwidth. The near infra redemitting lanthanides, Yb, Nd, Er have characteristic profiles which range from 900 nm to 1500 nm. Their applications in photonic devices is limited from the low quantum yield of emission due to their poor absorption characteristics.

Outcomes

The studies will develop novel plasmonic surfaces with lanthanide luminescent signals enhanced by the structural designs. A modelling methodology for topological design of tthe surfaces will be developed for both visible and near-infra red emitting lanthanides.

Methodology

Lanthanide emitter complexes will be designed based on previous expertise, using surface active groups to covalently attach the lanthanide complexes on surfaces. The computational modelling will be based on commercial full-wave electromagnetic software like Ansys Lumerical and Comsol Multiphysics, and plasmonic surfaces will be accordingly be prepared using nano and photolithography techniques.

Photophysical studies on surfaces will be evaluated using time-resolved and luminescence spectroscopy based on a state of the art spectroscopy setup coupled to microscope for imaging.

This project will benefit from close synergy with the EU funded H2020 Rise “Non-Conventional Wave Propagation for Future Sensing & Actuating Technologies” project and the EPSRC UK Metamaterials network led by the University of Exeter - the proposed PhD project falls within the remit of both of them.

Advert information