Influence of Tm3+concentration on spectroscopic transitions in visible and near-IR range of boro-tellurite glasses

Thulium (Tm3+)-doped boro-tellurite glasses were prepared by melt -quenching technique and their optical, photo -luminescence (PL), and time -resolved spectroscopic behaviors were studied. The Judd-Ofelt (J -O) parameters were calculated from the absorption spectra and evaluated the radiative factors for emission transitions. The PL and up -conversion (UC) emission spectra were measured under the excitation wavelengths of 473, and 793 nm diode lasers, respectively. The emission peak of 3H4 -> 3H6 (793 nm) and up -conversion 3F2,3 -> 3H6 (696 nm) transitions shifted to higher wavelengths with the increment of Tm2O3 concentration, while the 1G4 -> 3F4 (650 nm), 3H4 -> 3F4 (1466 nm) and 3F4 -> 3H6 (1821 nm) transitions showed no change in peak positions, under 473 nm laser excitation. The time -resolved spectroscopic measurements are recorded and analysed for all transitions. Under 793 nm laser, NIR emission spectra (1200-2200 nm) and spectroscopic characteristics were measured to discuss the energy transfer mechanisms. The strong transitions of 3H4 -> 3F6 (1466 nm) and 3F4 -> 3H6 (1821 nm) were observed and corresponding emission cross-section and gain factors have been evaluated and discussed for the application of the S -band communication window.