Decay curves of 1.5 μm (4I13/2) and 1.0 μm (4I11/2) emissions from Er3+ ions in Ga 2S3-GeS2-La2S3 glasses were measured by the excitation of a 1.5 μm and a 980 nm laser diode pump. The decay curves were simulated using rate equations for a model consisting of six levels of the Er3+ from the ground state. The rate equations contained five unknown parameters, i.e., excited state absorption cross sections of 4I13/2 → 4I9/2 (σesa24) for 1.5 μm excitation and 4I 11/2 → 4F7/2 (σesa36) for 980 nm excitation, cooperative upconversion coefficients of ( 4I13/2, 4I13/2) → ( 4I9/2, 4I15/2) (C2) and (4I11/2, 4I11/2) → ( 4F7/2, 4I15/2) (C3), and an energy back-transfer coefficient of (4I9/2, 4I15/2) → (4I13/2, 4I13/2) (C2r). These parameters were estimated by fitting the simulated curves to the measured ones. The obtained values were σesa24 = 0.3 × 10-20 cm2, σesa36 = 0.5 × 10-20 cm2, C 2 = 30-40 × 10-18 cm3/s, C3 = 20-25 × 10-18 cm3/s, and C2r = 5 × 10-18 cm3/s.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry