Investigation On Novel 2?m Luminous Heavy Metal Oxide Glass

2?m lasers can be widely applied in various fields,including military radar,environmental monitoring,biomedical,communications,etc.Currently,2?m laser gain medium mainly includes silicate glasses,fluoride glasses and heavy metal oxide glasses.The germanate-tellurite glasses have low phonon energy with good mechanical properties and thermal stability,which is a good laser glass matrix material.This thesis mainly conducts a research on the design and preparation of novel heavy metal oxiede glasses doped with rare earth ions as well as its emission properties at 2?m band,so as to obtain 2?m band laser gain dielectric materials.The main research contents of this thesis are as follows:1.The germanate-tellurite glass(Ge O₂-Te O₂-Nb₂O₅-K₂CO₃-Al₂O₃)was designed and prepared with the germanium oxide as the main glass former.In this kind of glasses,the glass transition temperature was 529°C and?T=195°C.In addition,the tellurite-germanate glass(Te O₂-Ge O₂-Nb₂O₅-K₂CO₃-Al₂O₃)was designed and prepared with tellurium oxide as the main glass former.In this kind of glass,the glass transition temperature was 390°C and?T=218°C.The results reveal that both of the above two glasses possess excellent thermal properties.2.The research on the emission properties of Tm³⁺doped and Tm³⁺/Ho³⁺co-doped 2?m was conducted in tellurite-germanate glasses.Moreover,Judd-Ofelt intensity parameters were calculated by the absorption spectra and fluorescence spectra,and the absorption and emission cross sections of these samples were analyzed.Furthermore,the energy level transitions and energy conversion methods of the sample glasses were studied.It was found that when the doping concentration of Tm³⁺was 0.4mol%,the?2?m fluorescence intensity of the sample glass was the strongest.The absorption and emission cross sections were calculated.Simultaneously,the gain property of the sample was analyzed,and the fluorescence lifetime of the sample doped with0.4mol%Tm³⁺was obtained to be 2.49ms.In Tm³⁺and Ho³⁺co-doped tellurite-germanate glasses,the J-O parameters were calculated by absorption spectra.The spontaneous emission transition rates of Tm³⁺and Ho³⁺were 329.13s^-1 and 68.91s^-1,respectively.It was found that when the doping concentrations of Tm³⁺and Ho³⁺were 1mol%and 0.1mol%respectively,the emission peak of the 2?m broadband was the strongest,the FWHM could reach 369nm,and the emission cross sections were 7.0×10^-21cm²and 1.3×10^-21cm².The effects of La₂O₃ and Ti O₂ on the?2?m emission properties of Tm³⁺doped glass were studied.It was found that the addition of 1mol%La₂O₃ was beneficial to improve the emission intensity of the sample,and the lifetime of the glass was increased,indicating that La₂O₃ composition was beneficial to improve the emission property of the glass.Ti O₂ had no significant effect on the improvement of glass property.3.In Yb³⁺and Ho³⁺co-doped tellurite-germanate glass,Yb³⁺provided a good sensitization for Ho³⁺so that the sample glass could be effectively excited by a980nm laser source.When the doping concentrations of Yb³⁺and Ho³⁺were0.3mol%and 1mol%respectively,the emission intensity reached the maximum.By calculation,the absorption and emission cross sections of Ho³⁺were 3.57×10^-21cm²and 4.27×10^-21cm²,respectively.The energy transfer between the two ions was analyzed,and the results showed that there was an effective transfer of the energy between Yb³⁺:²F_5/2 and Ho³⁺:⁵I₇.