Tm3+离子掺杂的钨酸钇钠晶体中浓度猝灭效应的研究

测量了Tm³⁺离子不同浓度(0.5at.%, 3 at.%, 5 at.%)掺杂的NaY(WO₄)₂晶体在800nm激光二极管激发下的上转换发射光谱.结合吸收谱、荧光谱和由Judd-Ofelt理论计算的光谱参数，详细分析了Tm³⁺:NaY(WO₄)₂晶体中上转换能量传递机理和离子浓度对上转换发射的影响.讨论了四种影响上转换发光效率的离子间相互作用机理：³H₅+¹G₄→³H₆+¹D₂，³H₅+³H₅→³H₆+³F₃，¹G₄+³H₆→³F₄+³F₃，¹G₄+³H₆→³F₃+³F₄，并根据Miyakawa-Dexter理论定量计算了各过程的发生概率.论证了交叉弛豫和共协上转换等浓度猝灭效应是影响Tm³⁺离子蓝色上转换荧光发射效率的主要因素. 关键词： 3+离子')" href="#">Tm³⁺离子 4)₂晶体')" href="#">NaY(WO₄)₂晶体 上转换 浓度猝灭

Investigation of concentration quenching effect in Tm3+-doped NaY(WO4)2 crystal

Upconversion blue emissions of Tm³⁺ ions with different doping (0.5at.%, 3 at.%, 5 at.%) in NaY(WO₄)₂ crystals are investigated under 800nm diode laser excitation. The upconversion mechanism and the dependence of upconversion efficiency on ion concentration are analyzed with respect to the absorption spectra, fluorescence spectra, and parameters calculated by Judd-Ofelt theory. Four ion-ion interaction processes: ³H₅+¹G₄→³H₆+¹D₂, ³H₅+³H₅→³H₆+³F₃, ¹G₄+³H₆→³F₄+³F₃,¹G₄+³H₆→³F₃+³F₄, which influence the upconversion dominantly in Tm³⁺ heavy-doped system, are demonstrated theoretically and experimentally. The results indicate that cross-relaxation and cooperative upconversion are the dominant processes affecting the blue emission efficiency.