Seminar Announcement: Angela Seddon
Data pubblicazione: 13-set-2018 7.44.08
Tuesday, 11 September 2018, 15:00
Sala Grande Palazzina B via alla Cascata 56/C
"Towards rare earth doped mid-infrared fibre lasers"
Chair of Inorganic Materials. Head of Mid-Infrared Glasses Group, GGIEMR, Faculty of Engineering.
University of Nottingham, UK
The progress made towards mid-infrared (MIR) fibre lasers will be described. Despite ongoing work since the late 1990s, fibre lasing above 4 microns wavelength in the MIR region has not yet been demonstrated. Current modelling has not uncovered all of the reasons for this lack of success. Photoluminescence and long photoluminescent lifetimes have been observed for rare earth ions such as Dy(III), Pr(III), Tb(III) and Ce(III) doped into selenide chalcogenide-glasses. Long PL lifetimes in small-core fibre will be shown. The underlying problem of impurities in the glass host causing extrinsic absorption has been modelled to reveal the true rare earth ion absorption cross-sections. The possibility of these unwanted impurities causing non-radiative depopulation of rare earth ion excited states will be addressed. In addition, the possibility of interference in the excited state dynamics of rare earth ions of the WAT (weak absorption tail) will also be introduced.