Systematic studies of cooperative upconversion and Yb3+-Er 3+ energy transfer in newly developed phosphate glasses were performed by a rate-equation formalism. The cooperative-upconversion coefficients of the 4I13/12 level for different Er 3+ concentrations were determined from the luminescence-decay curves for high pump intensities. A small cooperative-upconversion coefficient of 1.1 × 10-18cm3/s was obtained for a high Er 3+ concentration of 4 × 1020 ions/cm3. Yb3+-Er3+ energy-transfer coefficients for an Er 3+ concentration of 2 × 1020 ions/cm3 codoped with different Yb3+ concentrations were calculated from the lifetime measurements of the 2F5/2 level of Yb 3+ ions. For Er3+ codoped with an Yb3+ concentration of 6 × 1020 ions/cm3, an energy-transfer coefficient of 1.1 × 10-16 cm3/s and an energy-transfer efficiency higher than 95% were determined from our measurements under weak excitation. The cooperative-upconversion coefficients of Yb3+-Er3+-doped samples were found to be consistent with that of an Er3+-doped sample with the same Er3+ concentration. The weak cooperative-upconversion effect of high Er3+ concentrations and efficient Yb3+-Er3+ energy transfer indicate that these newly developed Er3+- and Yb3+-Er 3+-doped phosphate glasses are excellent for active device applications.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of the Optical Society of America B: Optical Physics|
|Publication status||Published - 2000|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics