Spectroscopic properties and energy transfer process in Tm3+-doped Silica-germanate glasses

A Tm3+-doped silica-germanate was successfully prepared by high-temperature melting method in this work and compared with traditional silicate and germanate glasses comprehensively. The DSC results indicated a better ability against thermal damage (higher Tg=636 °C) compared with silicate glass together with better thermal stability (ΔT=106 °C and S=3.17) than germanate (ΔT=99 °C and S=2.64) glass. Intense 1.8 μm emission in the silica-germanate glass was also obtained when pumping by an 808 nm laser diode, which possessed larger peak absorption and emission cross section (3.15×10-21 cm2 and 7.08 ×10-21 cm2). Finally, the structure analysis suggested a low phonon energy and high rare earth ions solubility in silica-germanate glass through Raman spectra and X-ray photoelectron spectroscopy. All results indicate that the prepared silica-germanate glass is a promising candidate for 2 μm laser applications.