Research objectives and content
This two year project is dedicated to investigation of photoinduced refractive index changes in rare-earth-doped fluoride crystalline materials and glass waveguides by means of spectroscopy methods including photoconductivity and modelling of the physico-chemical processes. The aim of this project is to investigate the spectroscopy of the various ionised rare earth species of which the energy levels are close to the energy band gap of the material. The objectives will be to provide reliable models accounting for the photoinduced properties. The methodology involves several steps from bulk materials (crystals and glasses) to waveguides and theoretical aspects from identification of excited species to excited state dynamics and electronic delocalization. Experiments on bulk materials and waveguides will include absorption, laser induced fluorescence and photoconductivity measurements under selective laser excitation. A selection of crystalline materials, fluoride elpasolite type, and glass waveguides will be investigated with different rare earth doping. This process has started during this year with some bulk materials like Rb2KInF6 and thin films like PZG glasses, doped with Eu3+; Ce3+, Er3+ and Tb3+ ions . With the knowledge of the energy level physics and dynamics, modelling will provide a full description of oxydo-reduction processes and photosensitivity mechanisms and will allow to handle practical use of refractive index change in fluoride devices.
Training content (objective, benefit and expected impact)
The use of spectroscopic techniques already established in the LPCML, like the guided luminescence and Raman spectroscopy, the development of new experimental set-up, like the photoconductivity measurements, and the collaboration between different laboratories in such an actual topic are a very suitable extension for my training from an experimental, technological, theoretical and human viewpoint
Links with industry / industrial relevance (22)
The industrial interest of the project is evident because it is closely related to waveguide applications for which the host institution and several French laboratories are involved through a national granted program. The project is related to a Community programmeinvolving several European Laboratories from Universities (Lille, Southampton...) and industry (Alcatel). |