Bingpeng Li

Quantitative Analysis of Energy Transfer and Origin of Quenching in Er3+/Ho3+ Codoped Germanosilicate Glasses

The energy transfer mechanism between Ho(3+) and Er(3+) ions has been investigated in germanosilicate glass excited by 980 nm laser diode. A rate equation model was developed to demonstrate the energy transfer from Er(3+) to Ho(3+) ions, quantitatively. Energy transfer efficiency from the Er(3+):(4)I13/2 to the Ho(3+):(5)I7 level can reach as high as 75%. Such a high efficiency was attributed to the excellent matching of the host phonon energy with the energy gap between Er(3+):(4)I13/2 and Ho(3+):(5)I7 levels. In addition, the energy transfer microparameter (CDA) from Er(3+):(4)I13/2 to Ho(3+):(5)I7 level was estimated to (4.16 ± 0.03) × 10(-40) cm(6)·s(-1) via the host-assisted spectral overlap function, coinciding with the CDA (2,88 ± 0.04) × 10(-40) cm(6)·s(-1) from decay analysis of the Er(3+):(4)I13/2 level which also indicated hopping migration-assisted energy transfer. Furthermore, the concentration quenching of Ho(3+):(5)I7 → (5)I8 transition was the dipole-dipole interaction in the diffusion-limited regime, and the quenching concentration of Ho(3+) reached 4.13 × 10(20) cm(-3).

The influence of TeO2 on thermal stability and 1.53 μm spectroscopic properties in Er3+ doped oxyfluorite glasses

In this work, the thermal and spectroscopic properties of Er(3+)-doped oxyfluorite glass based on AMCSBYT (AlF3-MgF2-CaF2-SrF2-BaF2-YF3-TeO2) system for different TeO2 concentrations from 6 to 21 mol% is reported. After adding a suitable content of TeO2, the thermal ability of glass improves significantly whose ΔT and S can reach to 118 °C and 4.47, respectively. The stimulated emission cross-section reaches to 7.80×10(-21) cm(2) and the fluorescence lifetime is 12.18 ms. At the same time, the bandwidth characteristics reach to 46.41×10(-21) cm(2) nm and the gain performance is 63.73×10(-21) cm(2) ms. These results show that the optical performances of this oxyfluorite glass are very well. Hence, AMCSBYT glass with superior performances might be a useful material for applications in optical amplifier around 1.53 μm.

Synthesis, theoretical analysis, and characterization of highly Er 3+ doped fluoroaluminate–tellurite glass with 2.7 μm emission

The synthesis, theoretical analysis, and optical characterizations of fluoroaluminate–tellurite glasses with high Er3+ concentration are reported. The 2.7 μm emission from Er3+ doped fluoroaluminate–tellurite glasses upon excitation of a conventional 980 nm LD is demonstrated with minimized concentration quenching. The prepared glass possesses high fluorescence lifetime of 4I11/2 level (1.343ms) and large calculated emission cross section (7.63 × 10−21 cm2). Besides, the radiative transfer microscopic parameters of 4I11/2 and 4I13/2 levels were theoretically analyzed. Hence, these results indicate that this Er3+ doped fluoroaluminate–tellurite glass has potential applications in 2.7 μm laser.

Investigation of broadband mid-infrared emission and quantitative analysis of Dy-Er energy transfer in tellurite glasses under different excitations

Broadband mid-infrared emissions are obtained from Dy3+/Er3+ co-doped tellurite glasses under 808 or 980 nm excitation. The maximum effective emission bandwidths of mid-infrared emission is 92.45 nm in Dy3+/Er3+ co-doped tellurite glass pumped by 808 nm, while it can reach 209.00 nm pumped by 980 nm. The effects of different laser excitations on the energy transfer mechanism between Dy3+ and Er3+ ions have been investigated in tellurite glasses. Under 808 nm excitation, the energy transfer efficiency from Er3+:4I13/2 to Dy3+:6H11/2 level is 73.1% and the energy transfer coefficient from Er3+:4I11/2 to Dy3+:6H5/2 level and from Er3+:4I13/2 to Dy3+:6H11/2 level are 6.89 × 10−38 and 0.01 × 10−38 cm6/s, respectively. Under 980 nm excitation, the energy transfer efficiency from Er3+:4I13/2 to Dy3+:6H11/2 level can reach as high as 80%. Moreover, the maximum emission cross-section of 2500-3100 nm broadband emission when pumped by 808 nm is 1.90 × 1020 cm2 at 2765 nm, while it can reach as high as 4.99 × 1020 cm2 at 2724 nm pumped by 980 nm. Thus, the 980 nm excitation is more efficient for Dy3+/Er3+ co-doped tellurite glass to realize low-threshold and high gain applications at broadband mid-infrared laser.

Tunable mid-infrared luminescence from Er3+ -doped germanate glass.

Er(3+) -doped germanate glasses with superior thermal stability were prepared. Judd-Ofelt intensity parameters and important spectroscopic properties were discussed in detail. Upon 800 nm and 980 nm LD pumping, 2.7 µm fluorescence characteristics were investigated and it was found that the effective 2.7 µm emission bandwidth can reach to 101.79 nm in prepared glasses. The tunability of the 2.7 µm emission band can be realized by adjusting the Er(3+) content. Moreover, a high-emission cross-section (11.09 × 10(-21) cm(2) ), large gain bandwidth (772.30 × 10(-28) cm(3) ) and gain coefficient (6.72 cm(-1) ) were obtained in the prepared sample. Hence, Er(3+) -doped germanate glass might be a promising mid-infrared material for tunable amplifiers or lasers.