【作者】 唐剑锋； 陈雨金； 林炎富； 龚兴红； 黄建华； 罗遵度； 黄艺东；

【Author】 Jianfeng Tang Yujin Chen Yanfu Lin Xinghong Gong Jianhua Huang Zundu Luo Yidong Huang (Key Laboratory of Optoelectronic Materials Chemistry and Physics,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences)

【机构】 中国科学院福建物质结构研究所光电材料化学与物理重点实验室；

【摘要】 采用800nm附近的半导体激光泵浦Tm³⁺离子激活的固体材料是目前实现1.9μm激光的最主要方式。鉴于氧化铥中往往含有伴生的氧化铒杂质,本文采用795nm激光激发,发现微量（约50ppm）的Er³⁺杂质离子在7.5 at.%Tm³⁺离子掺杂的NaLa（MoO₄）₂基质中即可产生上转换绿光和红光发射。通过分析Er³⁺离子对Tm³⁺离子激发态能量的损耗机制,发现Er³⁺离子主要通过接受布居在³H₄和³F₄能级上的Tm³⁺离子的能量而实现上转换。采用能量传递理论计算了Tm³⁺与Er³⁺离子之间的能量传递参数。计算结果表明,虽然与Tm³⁺离子间的交叉弛豫相比,Tm³⁺与Er³⁺离子之间与浓度无关的能量传递微参量C_DA均较大,但由于能量传递几率同时受到杂质离子浓度的影响,即便是Er³⁺离子在晶体中的含量达到Tm³⁺离子浓度的0.1%（3N纯度Tm₂O₃原料的杂质上限）,其对Tm³⁺离子激发态能量造成的损耗率也不超过1%。这将为合理选择Tm³⁺离子1.9μm激光增益介质所需的氧化铥原料纯度以及优化其性能时提供参考。更多还原

【Abstract】 Laser diodes around 800 nm are widely used to pump Tm ions doped materials to realize the 1.9μm laser.The upconversion fluorescence emission of Er³⁺ trace impurity ions（～50ppm）,which probably originate from the starting chemical Tm₂O₃,as a loss of the excited energy of Tm³⁺ ions in Tm³⁺:NaLa（MoO₄）₂,was recorded under a 795nm laser excitation.The upconversion mechanisms were analyzed.Both the Er³⁺ upconversion green and red emission can introduce loss channel to the Tm³⁺ populating at the ³H₄ and ³F₄ multiplets relevant to the 1.9μm laser operation.By using the theory of energy transfer,the calculated concentration-independent microparemeter C_DA between Tm³⁺ and Er³⁺ ions is much larger than that of the cross relaxation between Tm³⁺ ions.However,taking the relatively low concentration of Er³⁺ ions into account,the energy transfer probability between Tm³⁺ and trace Er³⁺ ions is much smaller than those of the other transitions of Tm³⁺ ions,the actual loss caused by the Er³⁺ inpury ions is less than 1%to the whole energy of the ³H₄ Tm³⁺ ions for a 7.5 at.%Tm:NLM.This would be meaningful for selecting the Tm₂O₃ starting chemical with a right purity for the economic 1.9μm laser gain medium.更多还原