Rare-earth-doped and semiconductor nanocrystal lasers for photonic applications

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The project will pioneer micro-resonators made from rare-earth doped upconverting nanoparticles and/or luminescent semiconductor nanocrystals in order to enable novel microscopic/sub-microscopic lasers for use in photonic integrated circuits and as enhanced fluorescent/lasing labels for sensing and biomedical applications. Background: Luminescent nanoparticles (1nm to 50nm in size) can act as the building blocks of higher level, micrometre-scale photonic structures (super-crystals or super-assemblies) that can be designed for enhanced fluorescence and light matter-interactions, as well as for multi-functionalities. Our team has recently demonstrated micro-size lasers using semiconductor nanocrystals that self-assemble into microsphere resonators under the right conditions. These structures are a great platform to study laser phenomena at a very small scale. They also create opportunities for new applications in integrated optics (as microscopic light sources) and in biomedical sciences (for example as efficient fluorescent and sensing labels that could be used in-vivo). We are now expanding our "building blocks library" to rare-earth doped upconverting nanoparticles - these enable efficient anti-Stokes emission (e.g., they can emit in the visible or UV when excited by near infra-red light), an attractive feature for utilisation of microlasers within biological samples. Our first target is to demonstrate a self-assembled upconverted laser, which has never been reported so far.Our team is therefore pioneering these new types of microlasers with the underlying goals of understanding their physics, of revolutionising the way pathogens or pollutants are targeted and detected, and of establishing innovative artificial optical materials. This studentship will contribute to achieving these goals. It is envisaged that the focus will be on integration of these materials with photonic integrated circuitry (microfabrication of photonic elements by lithography and self-assembly, microlaser integration, and testing), although there is flexibility depending on the student background and aspirations.Objectives: As part of the team the student will work towards the following objectives:(i) Synthesise microlasers using bottom-up (self-assembly) and hybrid top-down/bottom-up fabrication approaches;(ii) Add functionalities to the microlasers (to be able to interact with and "sense" their environment) through surface engineering;(iii) Characterise the physical (material and morphology) and optical properties of the microlasers; progress understanding of physical processes in these microstructures;(iv) Integrate microlasers with photonic circuitry components - paving the way for novel integrated optics and lab-on-chip devices;(v) Initiate and develop applications