The mid-infrared emission properties and energy transfer of Tm3+ /Er3+ co-doped tellurite glass pumped by 808/980nm laser diodes

Abstract

The spectral performance of the Tm3+/Er3+ co-doped tellurite glass under the pump at 808/980 nm and the energy transfer process between Tm3+ and Er3+ were mainly studied. The mid infrared fluorescence spectra showed that when the concentration of doped Er3+ ion was 0.5mol%, the fluorescence intensity of 1.8 μm and 2.7 μm reached the peak. While at the pump of 980 nm, the maximum occurred in 1mol% of Er3+ ions. Under 808/980 nm pumping system, different energy transfer mechanisms between Tm3+ and Er3+ ions were accordingly proposed. The maximum emission cross section of 0.5 Tm3+/0.5Er3+ codoped sample can reach 4.68 × 10−21 cm2 at 1886 nm. When P was 0.4, the gain of Tm3+:3F4→3H6 at 1852–2100 nm started to be positive while its maximum gain coefficient was 0.91 cm−1, and its central wavelength was 1887 nm. Therefore, the large emission cross section and the high gain are conducive to the Tm3+/Er3+ co-doped tellurite glass to obtain low threshold value and high gain of the 2 μm laser output.