Study On The Preparation And Properties Of Thulium-doped High-gain Fluorophosphate Glass

2 μm laser has attracted wide attention due to its band characteristics and wide application in optical communication,medical,military and other fields.Up to now,there are many researchers study on 2 μm luminescent substrate glass materials,including silica glass,silicate glass,tellurite glass and fluoride glass,et al.In order to improve the gain of glass materials,it is necessary to find a kind of glass matrix with good comprehensive properties.Fluorophosphate glass combines the advantages of fluoride and phosphate glass,add the right amount of phosphate in fluoride glass can improve the viscosity,chemical stability and thermal stability of glass.It has low phonon energy,retaining the good optical properties of fluoride glass and have relatively low cost.To all,it is a kind of ideal output that can achieve high gain ideal material.Tm3+-doped fluorophosphate glass with large emission cross section and long fluorescence lifetime was prepared.Tm2O3 with different concentration gradients was used to explore the optimal doping concentration in this system.By changing the content of Ba(PO3)2,the effects of Ba(PO3)2 on the optical properties of Tm3+-doped fluorophosphate glass were investigated,and fluorophosphate glass with high gain coefficient was obtained.The effects of these changes on optical properties were investigated by changing the species of alkali metals and alkaline earth metals fluoride.The emission cross section of the glass was improved by introducing heavy metal oxides.The main content of this paper is as follows:This thesis consists of five chapters:the first two chapters are the literature review and basic theories of experimental characterization respectively.In the first chapter,the research status of 2 luminescent rare earth ion doped glass materials is summarized,the characteristics and research progress of 2 μm luminescent rare earth ion and matrix materials are concluded,and then the research ideas of this paper are proposed.The second chapter introduces some basic theories of preparation,measurement and calculation of fluorophosphate glass samples.In chapter 3,the components of fluorophosphate glass were determined,and a series of fluorophosphate glasses were prepared by changing the doping concentration of Tm3+ions,and the fluorescence characteristics of the glass were studied.Found in this paper,design of Tm3+-doped fluorophosphate glass has high solubility of rare earth ions,when the concentration of rare earth ions doped reaches 2 mol%,there has no fluorescence quenching phenomenon,but when the doping concentration reaches 2 mol%,glass began to crystallize.Finally,1.5 mol%was selected as the optimal doping concentration of the sample.Then,fluorophosphate glasses with different Ba(PO3)2 contents are designed and prepared.The physical,thermal and optical properties of Tm3+-doped fluorophosphate glasses were investigated by studying a series of fluorophosphate glasses with different Ba(PO3)2 contents.Research shows that add 20%Ba(PO3)2 to fluoride glass has good thermal stability as(AT=146℃),the smallest OH-absorption coefficient(αOH=0.36 cm-1),the longest fluorescence lifetime(τ=0.406 ms)and the biggest gain coefficient(σem×τm=3.045×10-21 cm2xms).Therefore,FP20 component was selected as the basis for subsequent studies.In the fourth chapter,the effects on the variety of fluoride of alkali metals,alkaline earth metals and the introduction of heavy metal oxides on their optical properties are studied.The results show that the introduction of NaF can reduce the thermal stability and gain coefficient of glass,but increase the emission cross section of glass slightly.In comparison,the comprehensive performance of LiF is better.The introduction of heavy metal oxide TeO2 will increase the emission cross section of the glass,making the emission cross section of the glass reach 1.599×10-26 m2.The introduction of MgF2 into the glass system will improve the gain coefficient of glass,while the introduction of CaF2 and SrF2 will reduce the fluorescence lifetime or emission cross section of glass,thus reducing the gain coefficient of glass.After continuous exploration of the structure,high-gain fluorophosphonate glasses doped with thulium are prepared,providing a new substrate choice for the 2 μm fiber laser field.The fifth chapter is the conclusion of this paper,summarizes the experiment and its results,points out the shortcomings of the paper and the outlook for the future.