Investigation On Infrared Luminescence Properties Of Dy³⁺ Doped And Dy³⁺ /tm³⁺ -codoped Chalcogenide Glasses

0.8⁵μm infrared lasers have extensive application prospects in the fields of remote sensing, environmental monitoring, laser radar, optical communication, bio-engineering , medical treatment, and etc. Chalcogenide glasses possessing the lower phonon energy , leads to a decrease in the multi-phonon relaxation enabling active transitions between the rare-earth levels in the near- and mid- infared ranges, and a large refractive index in chalcogenide glasses exhibits a large stimulated-emission cross section. Rare-earth doped chalcohalide glass may be a potential host material for infrared lasers due to its better rare earth dissolvability, lower energy of phonons and well thermal stability.In this dissertation, 65GeS₂-25Ga₂S₃-10CsI and GeS₂-Ga₂S₃-PbI₂ systems were choosen as the basic glasses, and samples doped with Dy³⁺ ions or codoped with Dy³⁺/Tm³⁺ ions were mainly fabricated. 65GeS₂-25Ga₂S₃-10CsI glasses doped with Dy³⁺ ions were crystallined, which formed glass-ceramics. The effect of microcrystalline on the near-and mid-infrared fluorescence properties of glasses was investigated.The near-and mid-infrared spectroscopic properties were studied in Dy³⁺-doped and Dy³⁺/Tm³⁺- codoped chalcohalide glasses, respectively. The optical parameters by means of Judd-Ofelt theory according to absorption spectrum were calculated in different glasses.The effects of compsitional optimization on the near-and mid-infrared fluorescence properties of glasses were discussed, and as was discussed, microcrystalline can effect their physical and optical properties, Which is more advantageous to find matrix materials for efficient infrared fluorescence output. All these works provide the theoretical and experimental basis in order to select the rare-earth doped materials to obtain mid-infrared fluorescence better.In exordium, the research progress of laser glass materials was introduced. The features of chalcogenide glasses and their applications of mid-infrared were generalized. The latest research progresses of rare-earth doped chalcohalide glasses , and the luminescence of near- and mid-infrared of Dy³⁺ doped chalcogenide glasses were reviewed in detail.In chapter two, the experiment methods were introduced, including the sample preparation procedures, the theory and measurements of physics, thermal and optical properties. And the theoretical backgrounds, including Judd-Ofelt theory, McCumber theory and so on, were presented.In chapter three, a serials of 0.3 wt% Dy³⁺-doped (100-x)(0.8GeS₂- 0.2Ga₂S₃) -xPbI₂ (x=5, 10 and 15, in mol) chalcohalide glasses were synthesized by melt-quenching technique. The refractive indexes, densities, absorption spectra, fluorescence lifetimes, near-and mid-infrared fluorescence of glass samples were measured. The optical gaps of martix glasses were analyzed by basis of their absorption spectra. The intensity parameters (Ω_t,t=2,4 ,6), transition probabilities (A_rad), branching ratios (β) and radiative lifetimes (Ï„_rad) have been predicted for Dy³⁺ ions in samples by using the Judd-Ofelt theory. The effect of PbI₂ content on the optical parameters and fluorescence properties of glasses was investigated, and also the multiphonon relaxation phenomena in Dy³⁺-doped Ge-Ga-S-PbI₂ glasses were evaluated and compared with other.In chapter four, A serials of Dy³⁺/Tm³⁺ codoped (100-x)(0.8GeS₂-0.2Ga₂S₃) -xPbI₂ (x=2.5,5,10,15 and 20, in mol) chalcohalide glasses were fabricated. Raman spectra, absorption spectra, near-and mid-infrared fluorescence of glass samples were measured. The effect of Tm³⁺ and PbI₂ content on the mid-infrared fluorescence properties of glasses was investigated. Rules of Tm³⁺â†'Dy³⁺ energy transfer were discussed. The emission cross sections(σemi) of the 2933 nm and 4315 nm fluorescences were estimated.In chapter five, A serials of 0.7 wt% Dy³⁺-doped 65GeS₂-25Ga₂S₃-10CsI (in mol) chalcohalide glasses were synthesized by melt-quenching technique. Matrix glasses were ceramic-processed by using heat treatment, in order to obtain transparent chalcogenide glass ceramics, which makes Dy³⁺ ions in lower phonon energy environment of local structure of ceramics than in matrix chalcogenide glass. They are expected to help more easy and efficient output of near-and mid-fluorescence, achieving the target of exploreing a new type of rare earth doped mid-infrared laserdielectric materials.The last chapter is the conclusion of the thesis. It summarizes the results of the present work and also points out the demerits and suggestions for further studies.