Spectroscopic properties of Er3+ and Nd3+ doped glasses with the 0.8CaSiO3–0.2Ca3(PO4)2 eutectic composition

Rods of glass with the composition 56CaO–35SiO2–9P2O5 (in mol%) were produced by the fast solidification of laser float zone melted precursors with the wollastonite (CS) and tricalcium phosphate (TCP) eutectic composition. This inverted glass with a high content of CaO modifier presents a high transparency optical window from 4 to 0.35 μm and is not hygroscopic. Its refractive index is n=1.65. The glass can be doped with rare-earth oxides up to relatively high doping levels without impurity crystallisation or aggregation effects. The Er3+ and Nd3+ absorption and emission spectra were measured at temperatures from 10 to 300 K for different doping concentrations between 0.07 and 4 wt%. The energy of the 4f levels was determined from the absorption and emission spectra. Judd–Ofelt intensity parameters were calculated and compared with those of other glass systems. The Nd3+ emissions from the 4F3/2 level were studied in detail. The lifetime in the less concentrated sample at 300 K is 330 μs and the peak cross-section of the 1.062 μm emission is 2.2×10−20 cm2. The decay time of the Er3+ emission at 1.539 μm is 7.75 ms and the emission cross-section 0.6×10−20 cm2. These values are well retained up to the highest doping levels.