Preparation And Properties Of Rare Earth Doped Fluoroindate Mid-infrared Glass

In recent years,the 2.7μm mid-infrared laser has attracted more and more attention,because of its wide application in medical diagnosis and treatment,military,atmospheric environment monitoring and other fields.2.7μm corresponds to the energy level transition of Er³⁺:⁴I11/2→⁴I13/2,which is relatively narrow and susceptible to non-radiative transition.In order to achieve high efficiency luminescence,it is necessary to use substrates with low phonon energy,such as fluorotellurite glass,tellurite glass and fluoride glass.Among these glasses,fluoride based glass has the lowest phonon energy,the highest infrared transmission range and the highest solubility of rare earth ions,which makes fluoride glass the best laser gain medium.Fluoride glass is divided into zirconium fluoride,aluminum fluoride and indium fluoride glass.Compared with zirconium fluoride and aluminum fluoride glass,indium fluoride glass has the lowest phonon energy and the best infrared transmission range.However,the traditional ZBLAN（Zr F4-Ba F2-La F3-Al F3-Na F）glass has poor anti deliquescence performance,which limits its use.Therefore,it is very important to explore a fluoride based glass with low phonon energy and certain anti deliquescence performance.Fluorescence lifetime and stimulated emission are two key indicators of the suitability of a gain material for laser output.In this paper,a kind of Er³⁺-doped fluoroindate glasses with long fluorescence lifetime and large emission cross section has been obtained,and the matrix glass has low phonon energy,high infrared transmission range and a certain anti deliquescence property.The best concentration of erbium ion was obtained by doping different concentration gradient of erbium ion.The luminescent properties,energy transfer and energy transfer efficiency of erbium thulium Co-doped in fluoroindate glasses were studied.The results show that the thermodynamic properties,luminescence and emission cross section of the glass are improved by adding appropriate amount of chloride ions into the erbium doped in fluoroindate glasses.Introducing appropriate amount of bromide ion into erbium-doped fluoroindate glasses can enhance the luminescence and increase the emission cross section.This paper consists of six chapters.The first chapter is the introduction.The main contents include the introduction of different rare earth ions,the discussion of various matrix glasses and the related research progress of fiber lasers.In the second chapter,the preparation,characterization and calculation methods of samples are introduced.In the third chapter,a new type of indium fluoride matrix glass is studied,which has good infrared transmission range and better anti deliquescence performance than ZBLAN glass.The optical properties of erbium ion doped with different concentrations in the matrix glass were investigated.It was found that the heavy doping of erbium ion was realized in the matrix glass,and the high fluorescence lifetime and large emission cross section were maintained at the high concentration of 4%mol.It is suitable for 2.7μm fiber laser gain medium.In the fourth chapter,Er³⁺/Tm³⁺Co-doped fluoroindate glasses are studied.Taking low phonon energy indium fluoride as the matrix glass,the physicochemical properties,mid infrared spectrum characteristics,fluorescence lifetime and energy transfer between Er³⁺/Tm³⁺Co-doped fluoroindate glasses are studied.It is found that Er³⁺/Tm³⁺Co-doped fluoroindate glasses can broaden the spectrum coverage and achieve multi broadband gain.In Chapter 5,the effects of chloride and bromine ions on the thermodynamic and optical properties of erbium doped fluoroindate glasses are studied.The thermodynamic properties,luminescence intensity and emission cross section of erbium-doped fluoride glass at 2.7μm were improved by the introduction of appropriate chloride ions.The emission intensity and cross section of erbium-doped fluoride glass at 2.7μm are improved by the introduction of appropriate bromide ion,and the cross section is larger than that of the introduction of chloride ion.It is shown that the halogen element with lower phonon energy is more beneficial to the gain of erbium-doped fluoroindate glasses,which provides a new gain medium for the study of 2.7μm fiber laser.The sixth chapter is the summary of this paper and the prospect of the future.