Studies On The Preparation And Optical Properties Of Erbium Doped Fluorosilicate And Fluorophosphates Glass Ceramics

In recent years,extensive attentions have been focused on the exploration of solid state laser operating in mid-infrared range,it was largely driven by its potential applications in laser surgery,laser radar,laser ranging,laser sensing and so on.Then it arise the intense studies on the laser gain medium in the middle infrared band.Due to its excellent optical properties,rare earth doped fluoride glasses have attracted intense attentions,since the fluoride glass have relative lower phonon energy compared with conventional oxide glass has,which is favor to achieve higher efficient luminescence.However,the poor physical and chemical stability of the fluoride glass limit its further application in high power solid state lasers.Oxide glass has better physical and chemical stability,while the higher phonon energy of the host glass matrix reduce the luminescence efficient of rare earth ions.In this work,we proposed to reduce the phonon energy of oxide glasses and then reduce the phonon energy of the erbium-surrounding environment to enhance the radiation transition of erbium ions.The main research contents and results of this paper are as follows:1.To reduce the maximum phonon energy of the silicate glass,we introduce a part of fluoride into the glass matrix.The calculated ?4 was reduced when introduce a part of fluoride which demonstrated the symmetry structure of erbium ions reduced.The introduced fluoride ions will occupy some part of sites where occupied by oxygen ions,thus,the phonon energy of the ambient environment of some part of erbium ion reduce,resulting in intense fluorescence at 2.7 ?m.The maximum gain of the glass at 1550 nm and 2700 nm was calculated to be 0.21^x 10-20 cm² and 1.31^x 10-20 cm²,respectively.2.In this chapter,we fabricated erbium ions doped silicate glasses embedded with CaF₂ nanocrystal and studied its optical properties.The heat treatment temperature was selected from the following points in the range of glass crystallization temperature and transition temperature: 660 ?,680 ?,700 ?,720 ?,840 ?.The crystallinity of the glass was decreased from 32.7 nm to 51.2 nm with the increase of the temperature.The luminescence intensity of the near-infrared and the mid-infrared band is gradually increased.And the emission at 2.7 ?m is more than doubled.The CaF₂ crystal was precipitated in the glass by heat treatment at 700 ?,while the glass still maintained a high transmittance?84%?.XRD was used to calculate the Ca F₂ crystal size of 32.7 nm.By studying the luminescent properties of erbium ions in fluorosilicate glass under different time heat treatment,the optimum heat treatment process was carried out for heat treatment at 700 ? for 2 h.3.The thermal stability of fluorophosphate glass was studied and the effect of heat treatment on the infrared fluorescence of fluorophosphate glass was studied.The thermal stability of fluorophosphate glass was studied.The results show that CaF₂ and SrF₂ crystals with low phonon energy are precipitated in the fluorophosphate glass during the heat treatment,and some other whispers of the CaF₂ and SrF₂ crystals are precipitated in the fluorophosphate glass at 450 ?,470 ?,490 ?,510 ? and 530 ? respectively.The sub-nanometer energy of the sub-energy decreases the phonon field energy around the erbium ion and enhances the fluorescence intensity of Er³⁺ in near-infrared and mid-infrared.By studying the heat treatment results at different temperatures and at different times,the optimum heat treatment temperature was obtained by heating at 510 ? for 2 h.