Rare Earth-Doped Metasurfaces for Upconversion and Photon Avalanching – README

In the README project, we aim at combining recent important results from the material science community, leading to efficient thulium-doped upconversion (UC) nanoparticles, and from the nanophotonic community which demonstrated strong light conversion enhancement through the control of both absorption and emission using periodic dielectric metasurfaces. Our objectives are twofold:
-Optimize the infrared and visible to UV light conversion in Tm3+ ions. Efficient UV light generation is of prime importance for key applications like depollution or solar fuel generation, as usual photocatalysts are only efficient if excited in the UV range. The approach we propose aims at taking the best profit of solar infrared photons and using a limited quantity of UC medium. Demonstrators combining optimized UC metasurfaces and catalysts dedicated to water splitting (typically TiO2-Pt) will then be realized.
-Explore and control the non-classical and strongly non-linear regime of photon avalanching in Tm3+ ions. Achieving low threshold photon avalanching is notably expected to open the way to infrared photon counting. Our final objective is to pave the way to the demonstration of an infrared avalanche photodetector based on the combination between UC metasurfaces enabling photon avalanching, and a classical silicon-based photodetector.
In order to reach these challenging objectives, we will develop a methodology combining the realization of high quality UC media using CVD and PLD processes, and their integration with periodic dielectric metasurface, enabling to control absorption and light emission. These UC metasurfaces will then be used to develop the targeted demonstrators.