荧光俘获效应对掺铒氧化物玻璃光谱性质的影响

Effect of radiation trapping on spectroscopic properties of Er^(3+)-doped oxide glasses

测试了不同掺杂浓度和样品厚度下掺铒磷酸盐和碲酸盐玻璃的吸收光谱、荧光光谱和荧光寿命,计算了Er3+离子在1·53μm处的吸收截面(σa)、发射截面(σe)、自发辐射跃迁概率(Arad)、辐射跃迁寿命(τrad)、以及辐射跃迁量子效率(η)等光谱参数.讨论了荧光俘获效应对掺铒磷酸盐和碲酸盐玻璃光谱性质及光谱参数的影响.结果表明即使在铒离子低掺杂浓度(0·1mol%Er2O3)下,荧光俘获效应也普遍存在于掺铒玻璃材料中,使得荧光寿命(τf)和荧光半高宽(FWHM)随样品的厚度和铒离子掺杂浓度增加而增大,导致碲酸盐和磷酸盐玻璃中τf分别增加11%—37%和6%—17%,FWHM分别增加15%—64%和11%—55%,使得掺铒玻璃材料的放大品性参数(σe×FWHM)也相应被估高.由于铒离子在碲酸盐玻璃中在1·53μm处吸收和发射截面重叠面积较大,加之铒离子在前者基质中的发射截面高于后者,使得掺铒碲酸盐玻璃中的荧光俘获效应高于磷酸盐玻璃.

The absorption spectra, fluorescence spectra and the lifetimes of ^4 I13/2 level of Er^3＋ -doped phosphate and tellurite glasses have been measured for sample with different concentrations and thickness. The absorption cross-section （ σa）, emission crosssection（ σe ）, spontaneous emission probability （ Arad ）, radiative lifetime （ τrad ） and quantum efficiency （ η ） of fluorescence around 1.53 μm of Er^3＋ -doped phosphate and tellurite glasses were determined. The effect of radiation trapping on the spectral properties and parameters of Er^3＋ -doped tellurite and phosphate glasses has been investigated. It was found that radiation trapping exists generally in erbium-doped glass hosts, even at low Er^3＋ -doping concentration （0.1 mol% Er2O3 ）. Due to radiation trapping, the values of the τrad of the Er^3＋ ：^4 I13/2 level in tellurite glasses increased about 11%--37 % with the sample thickness and erhium doping concentration, while in phosphate glasses τrad increased hy 6%--17%. The full-width at half maximum （FWHM）of fluorescence in tellurite glasses increased about 15 %--64%, with 11%--55 % for phosphate glasses. It caused a high overestimation onthe figure of merits （FOM） for amplifier bandwidth （σ e × FWHM）. The spectral overlap between the emission and absorption spectra in 1.53 μm hand is relatively larger in tellurite than in phosphate glasses, and values of the emission cross-section in tellurite glasses are larger than that in phosphate glasses. Consequently, the radiation trapping in tellurite glasses is more severel than that in phosphate glasses.