Influence of Au⁰ metallic particles on NIR laser emission of Yb³⁺ ions in Li₂O-HfO₂-SiO₂ glass ceramic

This study consists of the synthesis, characterization, and analysis of photoluminescence (PL) spectra for Li2O-HfO2-SiO2-Yb2O3 glass ceramics sensitized with small amounts of Au2O3. Using the results of XRD and X-ray photoelectron spectroscopy (XPS) studies indicated a progressive reduction of Au3+ ions into Au-0 metallic particles (MPs) with increase of Au2O3 content. Investigations into the infrared spectra highlighted a growing concentration of induced defects in the samples due to the increased proportion of Au-0 MPs. Optical absorption (OA) spectra exhibited a distinct band attributed to the F-2(7/2) -> F-2(5/2) transition of Yb3+ within wavelength range of 800-980 nm. Furthermore, a wide absorption band linked to the surface plasmon resonance (SPR) of Au-0 MPs was identified in the visible region. PL spectra, recorded at lambda(exc) = 450 nm, revealed a band between 980 to 1025 nm, associated with the F-2(5/2) -> F-2(7/2) transition of Yb3+ ions. Another emission band was observed due to the sp -> d transition of Au-0 MPs within the visible region. Observed enhanced PL emission from Yb3+ ions in the NIR range was ascribed to the energy transfer from Au-0 MPs to Yb3+ ions. Ultimately, it was deduced that Au-0 MPs played a pivotal role in enhancing the PL output of Yb3+ ions in the Li2O-HfO2-SiO2 glass ceramic. Thus, glass ceramics incorporating an optimal concentration of Au2O3 hold significant potential as materials for NIR lasers.