Yb^(3+)离子摩尔分数对Yb∶GAB晶体辐射陷阱的影响  

Influence of Yb^(3+) Mole Fraction on Radiative Trapping of Yb∶GdAl_3(BO_3)_4 Crystals

作　　者：廖金生[1] 黄艺东[2] 林炎富[2] 陈雨金[2] 罗遵度[2] 

机构地区：[1]江西理工大学材料与化学工程学院,江西赣州341000 [2]中国科学院福建物质结构研究所,福建福州350002

出　　处：《发光学报》2009年第2期167-173,共7页Chinese Journal of Luminescence

基　　金：赣州市有色金属技术创新公共服务平台(PT08006)资助项目

摘　　要：测量了一系列Yb3+摩尔分数(0.125…1)在Yb3+∶GdAl3(BO3)4晶体(Yb∶GAB)的室温偏振吸收光谱、发射光谱。为了揭示和消除辐射陷阱对Yb3+光谱性质的影响,分别测量了块状、粉末和稀释粉末样品的发射光谱。为了比较不同摩尔分数和不同方式辐射陷阱的影响,采用倒易法(RM)和Fuchtbauer-Ladenburg公式(FL)来计算发射截面。实验结果表明:随着Yb3+离子摩尔分数的增加,辐射陷阱效应对发射光谱的影响越来越严重。在发射光谱中,随着Yb3+离子摩尔分数的增加,短波段发射变弱,长波段发射变强,因此,提出了Yb∶GAB晶体中发射光谱的重心波长移动Δλ与Yb3+离子摩尔分数之间的经验关系来定量分析Yb3+离子摩尔分数变化对辐射陷阱的影响;采用稀释法能够很好消除辐射陷阱对发射光谱的影响,而粉末法对于低Yb3+浓度的样品能够比较好地消除辐射陷阱的影响,块状样品直接测量很难消除辐射陷阱的影响。Microchip lasers are miniature diode-pumped solid-state lasers with a sufficiently short thickness of gain media, so only a single longitudinal mode falls under the gain profile. In order to absorb the pump light fully, especially, for the Yb^3＋ ions with smaller absorption cross section than the Nd^3＋ , quite high concentra- tion of active ions in the laser material is necessary. The Yb^3＋ ions can be doped into the GAB host as high as 100% i.e. YbAl3 （BO3 ）4, while keeps the R32 structure due to the radius of the Yb^3＋ ion is close to that of the Gd3＋. This character displays that Yb^3＋ mole fraction may be adjusted freely in the GAB crystal without the distortion of the crystal structure. This is very important for a microchip laser medium since the concentra- tion of active ions is generally modified with the thickness of the mierochip for absorbing adequate pump power and making the laser operates effectively. So the Yb： GAB crystal with changeable Yb^3＋ mole fraction could be a good candidate for microehip laser medium. The polarized absorption spectra, emission spectra of Yb^3＋ -doped GdA13 （ BO3 ） 4 （ Yb： GAB） crystals with a series of Yb^3 ＋ mole fraction from 0. 125 - 1. 000 were measured at room temperature. From the polarized absorption spectra of Yb： GAB crystals at room temperature, it can be found that the or-polarized （E⊥c） absorption coefficient is larger than that of the π-polarized （E⊥c） at the same Yb^3＋ mole fraction. The 976 nm peak is the strongest absorption peak in the or-polarized, which can match the emission wavelength of InGaAs laser diode （LD）. It means this kind of crystal is suitable for LD pumping. Samples of powder and diluted powder of all the Yb： GAB crystals were also used in the spectral experi- ments to reveal and eliminate the effect of radiation trapping on the measured emission spectra. The emission cross sections of the Yb： GAB crystals obtained by means of the reciprocity method （RM） and the Fuchtbauer- La

关 键 词：Yb:GAB晶体 辐射陷阱 Yb“离子 

分 类 号：O482.31[理学—固体物理]