Optical absorption and fluorescence properties of Tm3+-doped K-Mg-Al phosphate glasses for laser applications

Metaphosphate glasses doped with different concentrations of Tm3+ ions have been prepared and characterized through absorption, emission and decay measurements at room temperature. The peak positions in the absorption spectra have been identified and analyzed using free-ion Hamiltonian model. Judd-Ofelt analysis has been carried out on the absorption spectrum of 1.0 mol% Tm3+-doped phosphate glass and the intensity parameters have been determined. These intensity parameters have been used to predict the radiative properties for the florescence levels of the Tm3+ ion. The emission spectra in the UV-VIS region have been recorded with an excitation wavelength of 355 nm. The branching ratios and stimulated emission cross-sections show that the 1D2 → 3F4 transition of Tm3+ ions can be used as the potential laser emission at ∼451 nm. Decay profiles for the 1D2 level of Tm3+ ions have been measured by monitoring the 1D2 → 3F4 transition. The decay curves exhibit non-exponential nature for all concentrations and are analyzed under the framework of Inokuti-Hirayama model. The results obtained in this paper have been compared with other reported Tm3+-doped glasses.