| Traditional rare-earth?RE?doped silica fiber has a low luminescent efficiency,high pump threshold,narrow infrared tunable range and challenge to achieve mid-infrared laser output,which cannot satisfy the needs of critical technologies such as ultra-capacity optical communications,fiber optic sensing,ultrafast technology,biomedical and lidar,severely restricts the development of the laser materials and devices.Exploring novel photonic glass has aroused widespread attention.Currently,tellurite glass has been widely used in ultra-broadband amplifiers,fiber lasers and nonlinear optical devices owing to its low phonon energy(700 cm-1),high RE solubility(1021 ions/cm3),full infrared transmittance?6?m?,excellent optical property,and tunable emission bandwidth,becomes a promising candidate for solving the above problems.However,there are some instinct limitations of tellurite glass need to improve,such as poor thermal stability,low laser damage threshold and so on.Therefore,how to improve those disadvantages and realize high efficient infrared luminescence in tellurite glass has become one of the hottest issues of glass science field currently.Based on the above background,this thesis aims to explore novel tellurite glass matrix with excellent glass forming ability,high glass transition temperature,and prominent thermal stability to achieve high efficient near-and mid-infrared luminescence.Afterwards,the laser performance of RE-doped novel tellurite glass will be estimated on this basis.This dissertation is divided into four chapters:In chapter 1,the research background,the unique structure and characteristics of tellurite glass as well as the latest research progress of the tellurite glass and fibers have been reviewed.Furthermore,the relationship between structure and characteristics of tellurite glass and the methods to improve its disadvantages are emphasized.Finally,the research purpose and research content of this thesis are represented.Chapter 2 is the investigation of predicted glass-forming region in tellurite glass based on the thermodynamic theory.The lack of useful data of glass formation range impeding the development of novel glass system.In order to solve this problem,the optimized glass-forming region of TeO2-Nb2O5-XmOn?X=Na,Zn,Bi?and TeO2-ZnO-YmOn?Y=Li,Na,Rb,Mg,Pb,Bi?ternary systems are predicted using thermodynamic theory in this chapter.Firstly,the calculated and experimental liquidus of binary subsystems in TeO2-Nb2O5-XmOn systems are compared,and the error between calculated and experimental data are analyzed in details subsquently.The precdicted glass-forming region of TeO2-Nb2O5-XmOn ternary systems correspond well with the actrual range recorded in literature,indicating the prediceted method is feasible for tellurite glass.Afterwards,based on the excellent glass forming ability and physicochemical properties of TeO2-ZnO glass system,the glass-forming region of TeO2-ZnO-YmOn ternary systems are predicted,and the influence of different second composition on the precdicted glass-forming region is discussed.This work is intended to explore novel tellurite glass matrix,improve its thermal and optical properties and lay the foundation for high-gain fiber laser.In chapter 3,the glass formation,structure,near-and mid-infrared optical properties of TeO2-MoO3-ZnO?TMZ?glass is explored for laser material applications.The glass-forming region is predicted via the“thermodynamic method”and then confirmed by some few sets of experiment.The fundamental characteristics of the TMZ glass such as glass structure,optical and spectroscopic properties are also investigated in detail by Raman,absorption,emission spectra and fluorescence decay curves.Interestingly,the vitrification,thermal and optical property of the present glass is significantly improved with the addition of MoO3.Furthermore,the near-and mid-infrared luminescence properties of Nd3+,Tm3+and Er3+doped TMZ glass are investigated.Nd3+doped TMZ glass reveal a higher emission cross section(3.12×10-20 cm2)and spectroscopic figure of merit(6.01×10-24 s·cm2)for the Nd3+:4F3/2?4I11/2 transition,indicating the potential applications of the TMZ glass in high power1.06?m laser.Meawhile,the luminescence properties of Tm3+and Er3+-doped TMZ glass are also indicated that the TMZ is an excellent candidate for infrared laser materials.Chapter 4 is the study of the glass formation,physical properties and efficient 2.7?m emission of Er3+-doped TeO2-Ta2O5-ZnO?TTZ?tellurite glass.In order to improve the laser damage threshold and luminous efficiency of Er3+-doped tellurite galss,an Er3+-doped TeO2-Ta2O5-ZnO?TTZ?tellurite glass has been investigated to explore its possible application in mid-infrared laser glass and fiber lasers.The glass-forming region of the ternary TTZ glass system was determined based on the thermodynamic calculation and experiments.The basic physical and optical properties of the TTZ glass were characterized in detail by using Raman,different scanning calorimetry,luminescence spectra and fluorescence decay curves.Intense 2.7?m emission of Er3+-doped TTZ glass is observed upon the excitation of 980 nm LD.The excellent thermal stability?maximum?T=264??,low maximum phonon energy(near 770 cm-1),high emission cross-section(0.82×10-20 cm2)and spectroscopic figure of merit(3.22×10-24 cm2·s)indicate that the Er3+-doped TTZ glass could be a promising candidate for efficient3?m fiber lasers and amplifiers. |
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