| Germanate laser glass continues to attract considerable research interest owing to its high solubility of rare earth ions,low phonon energy,excellent physical and chemical properties,high laser damage resistance threshold and wide infrared transmission range,which is expected to be used in communication,fiber laser and sensing fields.This thesis aims to explore a new kind of germanate glass matrix with excellent glass-forming properties,lower phonon energy,wider infrared transmission range,and lower melting temperature.Afterwards,rare earth ions were doped to evaluate the optical spectral characteristics of the new germanate glass and to investigate its suitability as a laser host.This dissertation includes the following four chapters.Chapter 1 is the introduction of the thesis.Firstly,the structure and characteristics of germanate glass is proposed.Then the research progress of germanate optical glass and optical fiber has been reviewed briefly.Finally,the research purpose and content of the dissertation are put forward.In Chapter 2,the preparation methods,testing and characterization measurement of germanate glass samples are introduced.The calculation principle of theoretical glass-forming region is also briefly described.In Chapter 3,the formation,structure,and optical spectral characteristics of a new germanate glass system Ba O–Sb2O3–Ge O2?BSG?are explored.The glass-forming region in BSG system is predicted quantitatively via the thermodynamic method and then determined experimentally.The differences between the theoretical and actual glass-forming region are analyzed in detail.Furthermore,the physical and structural characteristics of the glasses are also investigated as a function of the antimony oxide content.The results show that the incorporation of antimony oxide greatly enhances the glass-forming properties of glass,reduces the phonon energy,widens the infrared transmission range,and increases the density and refractive index.Using Nd3+and Er3+ions doping as examples,the optical spectral characteristics of BSG glass are studied.Nd3+-doped BSG glass exhibits excellent spectral parameters such as longer fluorescence lifetime?200.58?s?and large emission cross section(3.02×10–20 cm2),indicating that BSG glass has great potential for fiber lasers in 1.06?m region.In addition,strong fluorescence emission of 2.7?m of Er3+in BSG glass host has been observed with large emission cross sections(9.53×10-21 cm2).demonstrating BSG glass is a promising matrix material for laser glass in the 2.7?m region.In Chapter 4,the formation,physical properties and 2?m luminescence characteristics of Ba O–Zn O–Ge O2?BZG?glass are studied.2?m region fiber laser is the important application field of germanate glass.This chapter explores the basic properties and spectral performance of Tm3+-doped BZG glass in detail,and estimates its application prospect in the 2?m region.Firstly,the glass-forming region of BZG glass was predicted and formulated.Then,the physical properties and luminescence characteristics of glass were analyzed by means of prism coupling instrument,Raman spectroscopy,differential scanning calorimeter?DSC?,thermal expansion,thermal conductivity,absorption and emission spectroscopy and other testing methods.The results show that BZG glass has better thermal stability??T=135°C?,lower phonon energy(840 cm–1),better mechanical properties?hardness is 4420 MPa,elastic modulus is 63.7 GPa?,as well as small thermal expansion coefficient(8.35×10–6 K–1)and large thermal conductivitytransition)was obtained in the Tm3+-doped BZG glass with excellent spectral parameters such as emission cross section(6.07×10–21 cm2)and spectral quality factor(2.40×10–24s?cm2),suggesting that BZG glass can be used as an alternative host material for 2?m fiber lasers. |
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