Fluorescence features of Tm3+-doped multicomponent borosilicate and borotellurite glasses for blue laser and S-band optical amplifier applications

Abstract

Novel B2O3-SiO2-Al2O3-ZnO-Li2O/MgO and B2O3-TeO2-PbO-ZnO-Li2O-Na2O glasses with different concentrations of Tm2O3 were synthesized by using the melt-quench method. All the fabricated samples have been characterized by visible emission spectra and decay times, including near-infrared (NIR) luminescence measurements. For 0.5 mol% Tm3+-doped borotellurite glass, several radiative parameters are evaluated using the Judd-Ofelt parameters. The intensity of all the visible emission bands increased with the increase of Tm2O3 concentration up to 0.5 mol%, and beyond this doping content, luminescence concentration quenching takes place. The luminescence intensity quenching is attributed to energy transfer (ET) processes through cross-relaxation (CR) channels. The visible luminescence decay curves were well fit with a single exponential (for Tm3+: D-1(2) level) and double exponential (for Tm3+: (1)G(4) level) functions for the multicomponent borosilicate samples, while Inokuti-Hirayama model was used for the multicomponent borotellurite glass D-1(2) level decay time fit. The derived decay lifetimes of the D-1(2) level are found to be much shorter than that of the (1)G(4) level. In Li2O (alkali) or MgO (alkaline) containing borosilicate samples, pumped under 808 nm laser diode, the H-3(4) -˃ F-3(4) (1.458 mu m) emission intensity increased from 0.1 to 2.0 mol% Tm3+ ion concentration, indicating negligible CR processes. The computed Full-Width at Half-Maximum (FWHM) values for the 1458 nm emission in 2.0 mol% Tm3+-doped Li and Mg series borosilicate samples are 117 and 125 nm, respectively, while the FWHM value for 0.5 mol% Tm2O3 content doped borotellurite glass is 118 nm. Following the analyzed visible and NIR optical results, the fabricated Tm3+ glasses could be useful for blue laser and S-band optical amplifier applications.