Dong Mei Shi

Influence of Sensitizer Concentration on the Upconversion Luminescence of NaYF4: Yb3+, Er3+ Nanoparticles

A series of NaYF4: Yb3+, Er3+ nanoparticles with different doping concentration were successfully prepared by the combination of coprecipitation and hydrothermal methods using sodium citrate as chelator. Upconversion luminescence can be observed in all of the samples at room temperature. Fixed the Er3+ concentration with 1 mol% unchanged, the effect of the Yb3+ concentration on the upconversion luminescence of NaYF4: Yb3+, Er3+ samples were studied when the doped Yb3+ concentrations were 0 mol%, 1 mol%, 2 mol%, 5 mol%, 10 mol% and 20 mol%, respectively. As increasing the Yb3+ concentration, the total intensity of the upconversion luminescence of the samples is increasing while the ratio of red to green emission increases firstly and then decreases. The maximum ratio value is 22.1 when the Yb3+ concentration is 10 mol%. It is found that the cross relaxation and cooperative sensitization effect are the reasons for the phenomenon above.

Luminescence Properties of Er3+/Tm3+-Doped Ga2O3-Bi2O3-PbO-GeO2 System Glasses

The visible and near infrared emission spectra of Er3+/Tm3+-doped Ga2O3-Bi2O3-PbO-GeO2 (GBPG) glasses excited at 808 nm are experimentally investigated. The results reveal that 1.53 µm emission were enhanced with an increase of Er3+ concentration. Furthermore, the incorporation of Er3+ into Tm3+-doped systems has also resulted in intense 522, 545 and 693nm upconversion emission intensity and an weak 660 nm red emission. The possible mechanism and related discussions on this phenomenon have been presented. The results show that Er3+/Tm3+-codoped GBPG glass may be a promising materials for developing laser and fiber optical devices.

Spectroscopic Properties of Er3+-Doped Ga2O3-GeO2-Bi2O3-PbO Glass

Spectroscopic properties in Er3+-doped Ga2O3-GeO2-Bi2O3-PbO（BP）glass have been investigated and their promising application as Er3+-doped fiber amplifiers (EDFA) has also been evaluated under the excitation of 980 nm. The important roles of Bi2O3 substitution for PbO on spectroscopic properties, such as Judd-Ofelt intensity parameters (t=2, 4, 6) and emission spectra of Er3+, have been studied. The calculated peak emission cross-section of the 4I13/2→4I15/2 transition of Er3+ ions are 16.03×10-21 cm2 when the substituted PbO content by Bi2O3 is about 25 mol. The product of the peak emission cross-section ( ) and the full width at half-maximum (FWHM) of the sample is~689.29×10-28 cm3, which is higher than that of Er3+-doped silicate, phosphate and ZBLAN glasses. It was found that the substitution of Bi2O3 for PbO provides two potentials: broadening the full width at half-maximum of 1.53 μm fluorescence and improving the values of FWHM× of Er3+. The results strongly support that the Er3+-doped BP2 glass could be identified as a promising material for achieving 1.53 μm fiber amplifier.

Luminescence Properties of Er3+-Doped Ga2O3-GeO2-Bi2O3-R2O (R=Na and K) for 1.53 μm Fiber Amplifier

An intense broadband 1.53-μm emission with a full width at half-maximum of 51.2 nm and peak emission cross-section of 8.58×10-21 cm2 of Er3+-doped Ga2O3-GeO2-Bi2O3-R2O (R= Na+, K+) glass have been obtained upon 980 nm diode-laser excitation. Effects of alkali metal ions on the thermal stability and spectroscopic properties of Er3+-doped Ga2O3-GeO2-Bi2O3 glass have been investigated. It is found that the incorporation of Na+ replacing K+ into Er3+-doped Ga2O3-GeO2-Bi2O3 glass can effectively improve the 1.53-μm emission and deduce upconversion luminescence .The results show that Ga2O3-GeO2-Bi2O3-Na2O glass might be an attractive host material for their application in C-band optical fiber amplifiers.

Effect of Eu3+ on Spectroscopic Properties and Energy Transfer in Er3+/Eu3+-Doped Ga2O3-GeO2 Glass

Spectroscopic properties and energy transfer (ET) in Er3+/Eu3+-doped Ga2O3-GeO2 glass have been investigated. Effects of alkali metal and alkaline earth metals ions on thermal stability of Er3+-doped gallate-germanium glass have been investigated. Simultaneously influences of Eu3+ codoping on the optical properties of Er3+-doped Ga2O3-GeO2-Na2O (GN) glass have been investigated and the possible ET mechanisms involved have also been discussed. Significant enhancement of the 1.53 µm emission intensity and decrease of upconversion (UC) fluorescence with increasing Eu3+ concentration have been observed. The results indicate that the incorporation of Eu3+ into Er3+-doped GN glass can effectively improve 1.53-μm and lower UC luminescence, which makes GN glass more attractive for their use in C-band optical fiber amplifiers.