WAVELENGTH CONVERSION MECHANISM IN INFRARED UP CONVERSION LASER

研究了稀土离子在Yb^&lt；3+&gt；和Tm^&lt；3+&gt；离子掺杂发光材料中的能量传递和迁移过程，以探索包括红外上转换激光材料在内的各种激光材料的优化设计过程。选择了不同的氟化物晶格作为基质材料，并对氟化物玻璃进行了对比研究。结果表明，即使在先前认为具有相似发光特性的晶格中，从Yb^&lt；3+&gt；到Tm^&lt；3+&gt；离子的能量传递系数也相差近一个数量级。研究还表明，能量传递系数依赖于施主浓度，特别是在较低的施主浓度时。将这些实验结果与几种解析模型以及模拟结果进行了比较。在随机游走模型上进行的计算机模拟结果表明，这些行为得到了系统的解释。研究结果对各种稀土离子掺杂材料的优化设计具有一定的参考价值。文中给出了几个相关的实验结果，即级联红外激光器的研制、新型固体光源的探索和分子束外延生长的ZnSe：Ge单晶层的光致发光特性。

Energy transfer and migration processes between rare earth ions have been investigated in Yb^<3+> and Tm^<3+> ion-doped luminescent materials for investigating optimization procedures in designing various laser materials including infrared upconversion laser materials. Various fluoride lattices were chosen as the host materials and fluoride glass was also investigated for the purpose of comparison. It has been shown that energy transfer coefficients from Yb^<3+> to Tm^<3+> ions differ nearly one order of magnitude even in the lattices previously considered having similar luminescence characteristics. It has been also shown that the energy transfer coefficients depend upon donor concentration, particularly at lower donor concentrations. These experimental results were compared with several analytical model as well as simulation results. It has been demonstrated that these behaviors are systematically explained with the results of computer simulation carried out on random walk model. The present results seem to be useful in carrying out optimization design of various rare earth ion-doped materials. Several relating experimental results performed during the period, namely, fabrication of cascade infrared laser, exploration of new solid state light sources and photoluminescence characterization of MBE-grown ZnSe : Ge crystal layrs, are included in the report.