Positive influence of Sm3+ ion on the ~ 2.85 µm emission in Yb3+/Ho3+ co-doped silica-germanate glass

In present work, a novel sensitized ion: Sm3+ activated Yb3+/Ho3+ co-doped silica-germanate glasses have been synthesized by melt quenching method. Absorption spectra and mid-infrared photo-luminescence of prepared glasses were characterized and compared in parallel. Quintuple enhancement of ~ 2.85 µm emission was achieved successfully in Yb3+/Ho3+ co-doped silica-germanate glass with 0.3 mol% Sm3+ addition, which also possesses a large stimulated emission cross section (14.9 × 10-21 cm2). Sensitized effect of Sm3+ and efficient energy transfer (ET) mechanism of Ho3+:5I7→Sm3+:6H13/2 in the co-doped silica-germanate glasses were investigated under 980 nm laser diode excitation. Moreover, decay profiles of Ho3+:5I7 level were measured to further examine the high ET efficiency (η) of Ho3+:5I7 to Sm3+:6H13/2, which confirmed the efficient population inversion of Ho3+ ~ 2.85 µm emission. All results indicate that the Yb3+/Ho3+/Sm3+ tri-doped silica-germanate glass is a promising candidate material for improving the Ho3+ ~ 2.85 µm fiber laser performance.