Investigation on 2μm rare earth ions doped fluorophosphate glass and fiber

2μm输出的固体激光器因为在医疗、光通信、环境检测以及军事上的广阔用途引起了越来越多的关注。目前，国内外对2μm激光输出的稀土离子掺杂材料的研究非常多，其基质主要有晶体、石英光纤、氟化物玻璃光纤和重金属氧化物玻璃光纤等，但关于氟磷酸盐玻璃光纤却鲜有报道。氟磷酸盐玻璃兼具了氟化物玻璃和磷酸盐玻璃的优点，同时它也具有成份可调性大、稀土离子掺杂浓度高等特点，是一种非常适合于2μm发光的材料。 本文首先研究了Al(PO3)3的含量变化对氟磷酸盐玻璃物化性能、光谱性能的影响，如氟磷酸盐玻璃的热稳定性、化学稳定性、硬度、吸收光谱、吸收发射截面等，并且跟氟化物玻璃和磷酸盐玻璃做了比较。研究发现含5mol%Al(PO3)3的氟磷酸盐玻璃具有最佳的热稳定性，比氟化物玻璃优良许多。因此选择了含5mol%Al(PO3)3的组分作为研究的基础组分。 其次，研究了氟磷酸盐玻璃中多种稀土离子掺杂方式的光谱性质，如Tm单掺、Yb-Tm双掺、Tm-Ho双掺、Yb-Tm-Ho三掺、Er-Tm-Ho三掺等，比较分析了它们的2μm发光特性，并且研究了它们的能量跃迁机理。研究发现Yb-Tm-Ho三掺的氟磷酸盐玻璃在980nm LD抽运下能获得最强的2μm荧光。 之后，在Tm单掺、Tm-Ho双掺、Yb-Tm-Ho三掺和Yb-Ho双掺的氟磷酸盐玻璃中，研究了不同的稀土离子掺杂浓度对氟磷酸盐玻璃的2μm发光性能影响，寻找了各种掺杂方式下2μm发光的最佳稀土离子掺杂浓度。 最后，制备了Tm单掺的氟磷酸盐玻璃光纤，测试了它的2μm激光性能，获得了十几毫瓦的激光输出。2μm laser emission has drawn considerable attention because of its numerous applications including medical application, optical communication, environmental test and military area. Up to now, there are many reportes about rare earth ions doped materials for 2μm application, such as crystal, silica fiber, fluoride glass fiber and heavy metal oxide glass fiber. However, few researches about fluorophosphate glass fiber have been reported. Fluorophosphate glasses possess the merits of both fluoride and phosphate glasses, and are characterized with extensive compositions and high content of doped rare earth ions, which make them suitable optical materieals for 2μm emission. Firstly, the effect of Al(PO3)3 content on physical, chemical and optical properties of fluorophosphate glasses，such as thermal stability, chemical durability, hardness, absorption spectra and cross sections, is investigated and compared with fluoride and phosphate glasses. The fluorophosphate glass, containing 5mol% Al(PO3)3 content, possesses the best thermal stability and much better than fluoride glasses. Therefore, the glass composition with 5mol% Al(PO3)3 content is chosen for the later research. Secondly, the optical properties of several kinds of rare earth ions doped systems in fluorophosphate glasses, including Tm singly-doped, Yb-Tm doubly-doped, Tm-Ho doubly-doped, Yb-Tm-Ho triply-doped and Er-Tm-Ho triply-doped, are studied. The 2μm emission performance of them are compared and analyzed, and the energy transfer mechanisms are discussed. From the results, Yb-Tm-Ho triply-doped fluorophosphate glasses can achieve the most intense 2μm fluorescence. Thirdly, the effect of doped rare earth ions concentration on 2μm emission properties in Tm singly-doped, Tm-Ho doubly-doped, Yb-Tm-Ho triply-doped and Yb-Ho doubly-doped fluorophosphate glasses is investigated and analyzed. And then the optimization of doped rare earth ions in each doping system is discussed. At last, Tm singly-doped fluorophosphate glass fiber is prepared, and the 2μm laser property is measured, in which over ten milli-watts 2μm laser is obtained