Nanoparticles of Er-doped glass produced by laser ablation of microparticles

Abstract

We report the production of Er impurity-doped glass nanoparticles (NPs) by laser ablation of doped glass microparticles entrained in a flowing argon aerosol. The NP composition for this process is similar to the starting feedstock material, so the manufacture of impurity-doped NP requires only an impurity-doped feedstock. In experiments, NPs with a relatively large mean size of 20 nm were produced to purposely not confine the fluorescence of the impurity; however, other valuable properties of the NPs such as low-temperature sintering were retained. We measured the resulting changes in stoichiometry using energy dispersive spectroscopy in both scanning electron microscopy and transmission electron microscopy. We measured the spectra from both sparsely deposited regions consisting of individual NPs and clusters of NPs, and densely deposited regions where the deposits formed nanostructured films. The spectra measured from sparse and dense deposits were similar; for samples stored for six months in atmospheric conditions, the fluorescence measured from isolated NPs was quenched, but not the fluorescence measured from the densely deposited nanostructured films. In samples in which the fluorescence was measured within weeks of deposition, the fluorescence lifetimes were found to be only 0.5 ms shorter than those of the starting microparticles, indicating that the nanostructure did not significantly influence the defect or impurity quenching of the Er ions.