Optical properties of Nd3+ and Er3+ ions in fluoro-phosphate glasses: Effects of P2O5 concentration and laser applications

Materials based on fluoride glasses have been recognized as potential hosts for trivalent rare earth ions for different applications, such as fiber lasers. A broad range of stability, an appropriate refractive index and the optimization of the optical and mechanical properties are important characteristics that need to be improved in these new materials. In this work, we made a systematic study of the effect of substituting BaF2 for P2O5 in the matrix: 35InF3–20ZnF2–(16 − x)BaF2–xP2O5–20SrF2–6GaF3–2NaF–1.0REF3, where RE = Nd3+, Er3+, with x = 4.0; 8.0; 12.0 and 16.0 molar concentration. In order to evaluate the material's thermal evolution, we obtained differential scanning calorimeter (DSC) measurements, noting the variations in the stability range. Measurements of the refractive index, absorption and luminescence at room temperature in the spectral range from 300 to 3200 nm were also obtained. An increase in refractive index with increasing P2O5 concentrations was observed. The behavior of phonons in the samples was observed through of the absorption intensity and the narrowing of the bands in the visible part of the spectrum; the width of the bands in the infrared region did not change. From the areas of the absorption bands, we calculated the oscillator strengths for the all of the samples, and using the Judd–Ofelt intensity model, we calculated the characteristic spectroscopic parameters. Furthermore, we analyzed the intensity parameter in Nd3+ and Er3+ doped glasses to determine the material's suitability for laser applications.