Optical Properties and Electron Paramagnetic Resonance Spectra of Zirconium Fluoride- and Hafnium Fluoride-Based Glasses Activated with MnO2 and EuF2

Abstract

We have studied luminescence and electron paramagnetic resonance (EPR) spectra of manganese- and europium-activated fluorozirconate glasses in the ZrF₄–BaF₂–LaF₃–AlF₃–NaF (ZBLAN) system and fluorohafnate glasses in the HfF₄–BaF₂–LaF₃–AlF₃–NaF (HBLAN) system in order to assess the oxidation state and spatial distribution of the activator ions. The manganese luminescence band has been shown to shift from the green (545 nm) to the red (610 nm) spectral region, and additional lines in the EPR spectrum of manganese have been observed to emerge in the EPR spectrum of manganese as a result of BaCl₂ substitution for BaF₂ in the ZBLAN glass. The ratio of the concentration of free activator ions to that of clustered ions has been estimated quantitatively. It has been shown that, at high doping levels, the manganese and europium ions in the glasses are predominantly clustered, and only a small part of them are present as isolated ions.