SPECTRAL AND LUMINESCENT PROPERTIES OF FLUOROPHOSPHATE GLASSES DOPED WITH YTTERBIUM AND ERBIUM
Naučno-tehničeskij Vestnik Informacionnyh Tehnologij, Mehaniki i Optiki
Fluorophosphate glasses are among the most promising media for ytterbium erbium lasers. The following advantages of this glasses are low OH-content, simple glass synthesis process and the possibility for a relatively high dope concentration of rare-earth ions (up to 15 wt %). The paper deals with complex investigation of the spectral and luminescent properties of fluorophosphate glasses doped with different concentration of ytterbium and erbium ions. Glass compositions based on
... on Ba(PO3)2-BaF2-СaF2-MgF2-AlF3-SrF2-YF3 with different erbium fluoride concentration (from 1 to 12.5 mol%) were synthesized by conventional high temperature method. Absorption cross-sections and Judd-Ofelt parameters were determined based on the measured absorption spectra data. Erbium ions luminescence was excited by titanium-sapphire laser at 975 nm. Stimulated emission cross section was calculated by McCumber method. Fuchtenbauer-Landenburg formula is used to calculate erbium ions radiation lifetime. Calculated integral values of the absorption cross section are greater than of conventional phosphate glasses and reach abs =1,37×10-18 cm-2 and em =1,39×10-18 cm-2. The maximum value of quantum yield was equal to 85% and was obtained for sample with the erbium concentration of 1×1020 cm-3. Increasing of erbium ion concentration from 1 to 12,9×1020 cm-2 results in reducing of quantum yield by 7%, due to the low content of hydroxyl groups in fluorophosphate glasses. These glasses are a promising material for lasers and amplifiers design operating at 1.5 μm wavelength.