Observation of efficient Er3+:4I11/2→4I13/2 transition in highly Er3+ doped germanosilicate glass

Highly rare earth（RE）ions doped glass laser materials can produce efficient single frequency mid-infrared laser. In this work, a series germanosilicate glasses with various high erbium-doping concentration (up to 4?mol%) and without concentration quenching are fabricated. Spectroscopic properties and energy transfer (ET) mechanism of efficient Er³⁺:⁴I_11/2 →⁴I_13/2 transition have been investigated in detail upon a conventional 980?nm Laser Diode. The dense structure of silicate glass can be dissolved effectively by the introduction of GeO_2, which was analyzed by Raman spectra, so that the compatibility and luminous intensity of RE ions were improved. The high predicted spontaneous transition probability (A_rad =?37.65?s^?1) based on the Judd-Ofelt theory and large calculated emission cross section (8.8?×?10^?21 cm²) are obtained. The above results indicate that these glasses are promising to be the single frequency mid-infrared laser material.