Enhanced emission of 27 μm pumped by laser diode from Er^3+/Pr^3+-codoped germanate glasses

A novel Er(3+)/Pr(3+) codoped germanate glass was fabricated and analyzed. Efficient emission at 2.7 μm from the glass was observed upon excitation of a conventional 980 nm laser diode. The 2.7 μm emission characteristics and energy transfer (ET) were investigated. Population inversions between ⁴I(13/2) and ⁴I(11/2) levels have been achieved, and an enhanced emission from 2550 to 2800 nm was obtained. Large ET efficiency of 95% indicates that the ET process from Er(3+) to Pr(3+) (⁴I(13/2), ³H₄)→(⁴I(15/2), ³F₃) is efficient and that Pr(3+) can enhance the emission of 2.7 μm by quenching the lower laser level of Er(3+) via ET.