Structure and spectroscopic properties of Er3+ doped germanate glass for mid-infrared application

Intense 2.7 μm emission derived from modified Er³⁺ doped germanate glass was reported. Raman spectrum analysis was carried out to grasp glass structure. Based on the absorption spectrum, the Judd–Ofelt parameters and radiative properties were calculated originated from Judd–Ofelt theory. 2.7 μm emission characteristics, stark splitting features and energy transfer processes upon excitation of a conventional 808 nm or 980 nm laser diode were carefully investigated. The prepared glass possesses high spontaneous transition probability (34.28 s⁻¹), large calculated emission cross section (13 × 10⁻²¹ cm²) and gain coefficient (5.4 cm⁻¹) for the ⁴I_11/2 → ⁴I_13/2 transition. These results indicate that Er³⁺ doped germanate glass has potential applications in mid-infrared lasers and amplifiers.