Preparation And Properties Of Aluminoborogermanate Magneto-optical Glass

At present,the development trend of magneto optical devices is high power,low cost and miniaturization.Tb³⁺,Dy³⁺doped magneto optical glass is widely used in Faraday isolator and optical sensor.Tb³⁺doped B₂O₃-Ge O₂-Al₂O₃-P₂O₅（BGAP）glass,Tb³⁺doped BGAP glass ceramics,Dy³⁺doped BGAP glass and Dy³⁺/Tb³⁺co-doped BGAP glass were prepared by high temperature melting process.The specific research contents and results are as follows:（1）BGAP magneto optical glass doped with different concentrations of Tb₂O₃ was prepared by melt quenching process.The effects of different Tb₂O₃concentrations on structure,physical properties,magneto optical properties and fluorescence properties of the BGAP glasses and the influence of wavelength on Verdet constant of BGAP glass were tested and analyzed.The Verdet constant of BGAP glass doped with 35 mol%Tb₂O₃reaches-140.15 rad/（T·m）.（2）The prepared Tb³⁺doped magneto optical glass was heat treated,and the structure,morphology,magneto optical properties and fluorescence properties before and after heat treatment were compared.X-ray diffraction analysis showed that the precipitated crystals were mainly Al PO₄,and infrared spectra also showed the existence and growth of Al PO₄microcrystals.The Verdet constant of BGAP glass-ceramics doped with 28 mol%Tb₂O₃and heat treated for 15 h reaches-118.32 rad/（T·m）,and its visible light transmittance reaches 81%.When the doping amount of Tb₂O₃ is 28 mol%,with the increase of heat treatment time,the Al PO₄ microcrystals gradually grows and the luminescence intensity of BGAP glass-ceramics gradually decreases.（3）Dy³⁺doped and Dy³⁺/Tb³⁺co-doped BGAP magneto optical glasses were prepared by high temperature melting process,and the magneto optical and fluorescence properties of all glasses were characterized.Under the excitation of 633 nm incident wavelength,the Verdet constant of BGAP glass doped with Dy₂O₃ at 35 mol%is-85.08 rad/（T·m）,Verdet constant of BGAP glass doped with Dy₂O₃ at 2 mol%and Tb₂O₃ at 33 mol%reaches-127.42 rad/（T·m）.The luminescence intensity of Dy³⁺/Tb³⁺co-doped BGAP glass decreases gradually with the concentration quenching caused by the increase of rare earth ion doping concentration.