Optical, thermal and luminescence properties of La2O3–Ga2O3–ZrO2 glasses co-doped with Tm3+/Yb3+ prepared by containerless technique

Bulk La2O3–Ga2O3–ZrO2 (LGZ) glass and Tm3+/Yb3+ co-doped LGZ glasses were synthesized successfully using containerless technique. Raman spectra result reveals that the matrix sample possesses the low maximum phonon energy of ∼642 cm−1. The glasses show good compatibility between large Abbe numbers (>31) and high refractive indices (nd > 1.93). Moreover, transmittance measurements reflect that the glasses have high infrared transmittance of ∼81.9%, small OH– absorption coefficient and long mid-infrared cut-off wavelengths (∼7.5 μm). The surface morphology of host glass was characterized by scanning electron microscopy (SEM) micrograph and energy dispersive spectroscopy (EDS) tests reflect that the doped compositions are distributed into the matrix glass homogeneously. The results of thermal analysis show that the glasses have good thermal properties (Tg > 769 °C). Excited by 980 nm laser, an intense 1810 nm fluorescence is obtained originating from the transition: 3F4 → 3H6 of Tm3+ ion, accompanied by upconversion emission. It can be observed that 1810 nm fluorescence has the highest intensity at 1 mol% Yb2O3 and owns broad full width at half-maximum (>245 nm), the luminescence intensity of 3F4 → 3H6 transition increases with rising temperature from 300 to 550 K. Furthermore, the value of energy transfer efficiency shows that Yb3+ can transfer energy to Tm3+ effectively. By fitting the attenuation curves, the lifetimes of 1810 and 474 nm emission can be acquired.