Fused silica fibers doped with nanocrystals are a promising concept to overcome the intrinsic limitations of fused silica. A particular example is the potential reduction of the high phonon energy of fused silica, which will allow using visible (lasers) transitions of rare earth ions by reduction of the multi-phonon quenching. So far, it was not well understood how the parameters of such a vitreous/crystalline bi-material influence the coupling of the phonons with the rare earth transitions. Thus, we developed a model, which allows to compute analytically how the size of the nanocrystals and the absorption of the surrounding host glass influences the rare earth ions lifetimes. Our results demonstrate that sufficiently low levels of quenching can only be expected for fused silica free of impurities or dopants that increase the multi-phonon absorption. This indicates that high-purity aluminosilicate glasses, in contrast to phosphosilicate and borosilicate glasses, are ideal hosts.
The model and first results were published recently in Optical Materials Express 11, 1631-1642 (2021) (https://doi.org/10.1364/OME.424116).
The work for this publication was realised in the Laser Components and Fibres group.
