Transparent ceramics are at the heart of modern magneto-optical materials providing promising opportunities for Faraday isolators.1.0 at%RE:Tb3Ga5O12(rare earth(RE)=Pr,Tm,Dy)transparent ceramics were successfully prep...Transparent ceramics are at the heart of modern magneto-optical materials providing promising opportunities for Faraday isolators.1.0 at%RE:Tb3Ga5O12(rare earth(RE)=Pr,Tm,Dy)transparent ceramics were successfully prepared by air sintering and sequential HIP technique using the coprecipitated powders as the raw material.All the powders have shown to be a pure cubic terbium gallium garnet(TGG)phase and exhibit good dispersion.Additionally,a change could not be observed in particle shape with the different doped ions.After the two-step sintering,all the obtained ceramics have good optical quality,and the in-line transmittances at 1070 nm are higher than 80%.Moreover,no secondary phase can be detected from the microstructures.However,the pores which remain entrapped in the ceramics can be noted.The Verdet constant of ceramic samples is optimized by RE doping,and the Verdet constant at 632.8 nm is about−143 rad·T^(−1)·m^(−1),which is about 5%higher than that of TGG ceramics.Finally,the thermo-optical properties of 1.0 at%RE:TGG transparent ceramics are compared.The annealed TGG ceramic showed the best thermo-optical properties,and the thermally induced depolarization of 1.0 at%Ce:TGG and 1.0 at%Tm:TGG was inferior to that of annealed TGG ceramic.展开更多
Transparent Gd_(2)O_(3)ceramics with a cubic crystal structure were successfully synthesized for the first time.The Gd_(2)O_(3)ceramics subjected to hot isostatic press(HIP)at 1070℃consisted of uniform grains of 2-3...Transparent Gd_(2)O_(3)ceramics with a cubic crystal structure were successfully synthesized for the first time.The Gd_(2)O_(3)ceramics subjected to hot isostatic press(HIP)at 1070℃consisted of uniform grains of 2-3μm,and only a few residual pores could be detected inside the materials.X-ray diffraction(XRD)shows that the obtained polycrystalline materials have a cubic crystal structure,and the transmission polarized light observation shows that there is no birefringence inside the materials,indicating inherent optical properties of the cubic crystal structure.The optical absorption edge is 640 nm(optical band gap:2.1 eV),and the transmittance in the visible to near-infrared region is 72%,which is close to the theoretical transmittance calculated from Fresnel loss.Verdet constant of this material is almost wavelength-independent,and it is diamagnetic since it has the opposite polarity to that of common paramagnetic materials.展开更多
MAGNETO-OPTICAL current transformers (MOCT) based on the Faraday Effect provide numerous advantages over the conventional transformers. However the commonly used materials in MOCT are crystals that are very expensive ...MAGNETO-OPTICAL current transformers (MOCT) based on the Faraday Effect provide numerous advantages over the conventional transformers. However the commonly used materials in MOCT are crystals that are very expensive and temperature dependence thus will cause many problems for the output signal. Cost efficient diamagnetic PbO-Bi2O3-B2O3 (PBB) glass system is fabricated in this study, for the aim of obtaining a good candidate glass with high verdet constant and good temperature resistance to replace crystals. A home-made optical bench was setup, calibrated and used for measuring the verdet constant of the fabricated glasses. Glass with composition of 50%PbO-40%Bi2O3-10%B2O3 in mol showed high Verdet constant (0.1533 min/Gauss.cm) and good value of the figure of merit (0.02635 min/Gauss), which can be considered as the ideal candidate for MOCT applications.展开更多
Non-stoichiometric Tb_(2)(Hf_(1-x)Tb_(x))_(2)O_(7-x)(x=-0.07-0.45)magneto-optical ceramics were fabricated by solid-state reactive sintering in vacuum combined with hot isostatic pressing(HIP)posttreatment without any...Non-stoichiometric Tb_(2)(Hf_(1-x)Tb_(x))_(2)O_(7-x)(x=-0.07-0.45)magneto-optical ceramics were fabricated by solid-state reactive sintering in vacuum combined with hot isostatic pressing(HIP)posttreatment without any sintering aids.The phase composition,densification process,microstructure,optical transmittance,and Verdet constant of Tb_(2)(Hf_(1-x)Tb_(x))_(2)O_(7-x)ceramics were investigated.The in-line transmittance of(Tb_(0.93)Hf_(0.04))_(2)Hf_(2)O_(7.07)ceramics with a thickness of 2.0 mm reaches 74.6%at 1064 nm.The Verdet constant of Tb_(2)(Hf_(1-x)Tb_(x))_(2)O_(7-x)ceramics is-153.4,-155.8,and-181.2 rad/(T-m)at the wavelength of 633 nm when x=-0.07,0,and 0.1,respectively.The Verdet constant increases with the increase of Tb content,and these values are higher than that of the commercial Tb_(3)Ga_(5)O_(12) crystal,indicating that non-stoichiometric Tb_(2)(Hf_(1-x)Tb_(x))_(2)O_(7-x)ceramics have a great potential for the application in Faraday isolators.展开更多
Heavy-metal-oxide (HMO) glasses attract much interest in many applications such as Faraday rotators, current sensors, etc., in the area of magneto-optic effects due to their unique magnetic-optical property, high refr...Heavy-metal-oxide (HMO) glasses attract much interest in many applications such as Faraday rotators, current sensors, etc., in the area of magneto-optic effects due to their unique magnetic-optical property, high refractive index and other interesting properties. However, during the melt-quenching process of these glasses, the high corrosive nature of the melt to the crucibles makes the fabrication of HMO glasses complicated and the properties of the obtained glasses show strong dependence on the crucible materials. Literatures reported that the gold and platinum crucibles are not suitable due to their contamination to the melt glasses, ceramic crucible was considered suitable for the melting of HMO glasses. In this work, magnetic-optical glasses within the system of PbO-Bi2O3-B2O3 have been prepared using different kinds of ceramic crucibles for the aim of finding the most suitable crucible for melting HMO glasses. The glass properties in terms of Verdet constant, thermal stability and UV-Vis-IR transmittance in function of different crucibles were studied and reported. It was found that the same batch of glasses prepared under same conditions (melting temperature, melting time and annealing process), but in different ceramic crucibles (coded as C1, C2 and C3) showed significant difference in properties such as glass forming ability, thermal stability, optical absorption in UV-Vis-IR and Verdet constant (0.0812 - 0.1483 min/G.cm). The ceramic crucible made of 25%Al2O3 and 75%SiO2 (C2) was found to be the most suitable for PbO-Bi2O3-B2O3 glass preparation, compared with platinum, gold, C1 and C3. Glasses melted with C2 exhibit good performance in magneto and optical property, as well as good thermal stability.展开更多
This paper summarizes the results of investigation of garnets Gd3Ga5O12 (GGG) on the basis of their optical activity. Dispersion of Verdet constant was measured in the visible light range and in a strong magnetic fiel...This paper summarizes the results of investigation of garnets Gd3Ga5O12 (GGG) on the basis of their optical activity. Dispersion of Verdet constant was measured in the visible light range and in a strong magnetic field. The applied technique, namely micropolarimetry, exhibits high resolution which corresponds to the type of polarization microscope used in the investigation.展开更多
In this paper, we first theoretically report the magnetic and magneto-opticalproperties in paramagnetic media under high external magnetic field. Considering the action of theexternal magnetic Geld H_e and indirect ex...In this paper, we first theoretically report the magnetic and magneto-opticalproperties in paramagnetic media under high external magnetic field. Considering the action of theexternal magnetic Geld H_e and indirect exchange interaction H_v, the characteristic of the magneticsaturation and the property of the Faraday rotation to be nonlinear with external magnetic Geld arepresented in paramagnetic NdF_3. In terms of our theory, the indirect exchange interaction plays auimportant role in the magnetization M and the Faraday rotation θ in NdF_3 under high externalmagnetic Geld. The theory is in good agreement with experimental results. On the other hand, areasonable explanation for the temperature dependence of the ratio of the Verdet constant to themagnetic susceptibility V/x is obtained.展开更多
建立了全光纤电流互感器（fiber-optical current transformer,FOCT）温度特性的数学模型。该模型充分考虑传感光纤的弯曲特性,结合光纤线性双折射的分布参数模型从本质上解释了温度对线性双折射的影响机理：由于传感环的弯曲性,温度变...建立了全光纤电流互感器（fiber-optical current transformer,FOCT）温度特性的数学模型。该模型充分考虑传感光纤的弯曲特性,结合光纤线性双折射的分布参数模型从本质上解释了温度对线性双折射的影响机理：由于传感环的弯曲性,温度变化会导致光纤横截面上的受力不对称,进而引起线性双折射;单位长度光纤的线性双折射相位差与温度变化量成正比,与光纤弯曲半径成反比。并结合光纤Verdet常数的温度特性综合量化了温度对FOCT的影响。采用COMSOL有限元分析方法实现光场、磁场、温度场、应力场的耦合并分析求解。仿真结果表明：双折射效应会使光波旋转角变小;光纤横截面上的应力差与温度变化量成正比,与光纤弯曲半径成反比;温度波动将引起线性双折射,进而使光波旋转角减小;结合Verdet常数得到了温度波动时FOCT的综合误差,与理论分析结果吻合。最后设计并搭建FOCT实验平台,进行线性度测试和温度循环测试。测试结果表明：实验误差与理论误差变化趋势基本一致;温度波动越大,FOCT误差漂移越严重,必须采取补偿措施,故提出一系列改善FOCT温度稳定性的方法。仿真与实验结果验证了理论分析的正确性。展开更多
基金supported by the National Key R&D Program of China(Grant No.2017YFB0310500)the NSFC-RFBR Cooperative Research Project(Grant No.61911530135)+1 种基金the Key Research Project of the Frontier Science of the Chinese Academy of Sciences(No.QYZDB-SSW-JSC022)supported partially by the Ministry of High Education and Science of the Russian Federation and the State Task executed in the Institute of Applied Physics RAS(Project No.00352019-0015)。
文摘Transparent ceramics are at the heart of modern magneto-optical materials providing promising opportunities for Faraday isolators.1.0 at%RE:Tb3Ga5O12(rare earth(RE)=Pr,Tm,Dy)transparent ceramics were successfully prepared by air sintering and sequential HIP technique using the coprecipitated powders as the raw material.All the powders have shown to be a pure cubic terbium gallium garnet(TGG)phase and exhibit good dispersion.Additionally,a change could not be observed in particle shape with the different doped ions.After the two-step sintering,all the obtained ceramics have good optical quality,and the in-line transmittances at 1070 nm are higher than 80%.Moreover,no secondary phase can be detected from the microstructures.However,the pores which remain entrapped in the ceramics can be noted.The Verdet constant of ceramic samples is optimized by RE doping,and the Verdet constant at 632.8 nm is about−143 rad·T^(−1)·m^(−1),which is about 5%higher than that of TGG ceramics.Finally,the thermo-optical properties of 1.0 at%RE:TGG transparent ceramics are compared.The annealed TGG ceramic showed the best thermo-optical properties,and the thermally induced depolarization of 1.0 at%Ce:TGG and 1.0 at%Tm:TGG was inferior to that of annealed TGG ceramic.
文摘Transparent Gd_(2)O_(3)ceramics with a cubic crystal structure were successfully synthesized for the first time.The Gd_(2)O_(3)ceramics subjected to hot isostatic press(HIP)at 1070℃consisted of uniform grains of 2-3μm,and only a few residual pores could be detected inside the materials.X-ray diffraction(XRD)shows that the obtained polycrystalline materials have a cubic crystal structure,and the transmission polarized light observation shows that there is no birefringence inside the materials,indicating inherent optical properties of the cubic crystal structure.The optical absorption edge is 640 nm(optical band gap:2.1 eV),and the transmittance in the visible to near-infrared region is 72%,which is close to the theoretical transmittance calculated from Fresnel loss.Verdet constant of this material is almost wavelength-independent,and it is diamagnetic since it has the opposite polarity to that of common paramagnetic materials.
文摘MAGNETO-OPTICAL current transformers (MOCT) based on the Faraday Effect provide numerous advantages over the conventional transformers. However the commonly used materials in MOCT are crystals that are very expensive and temperature dependence thus will cause many problems for the output signal. Cost efficient diamagnetic PbO-Bi2O3-B2O3 (PBB) glass system is fabricated in this study, for the aim of obtaining a good candidate glass with high verdet constant and good temperature resistance to replace crystals. A home-made optical bench was setup, calibrated and used for measuring the verdet constant of the fabricated glasses. Glass with composition of 50%PbO-40%Bi2O3-10%B2O3 in mol showed high Verdet constant (0.1533 min/Gauss.cm) and good value of the figure of merit (0.02635 min/Gauss), which can be considered as the ideal candidate for MOCT applications.
基金supported by the National Key R&D Program of China(Grant No.2021YFE0104800)the NSFC-RFBR Cooperative Research Project(Grant No.61911530135)the Key Research Project of the Frontier Science of the Chinese Academy of Sciences(No.QYZDB-SSWJSC022)。
文摘Non-stoichiometric Tb_(2)(Hf_(1-x)Tb_(x))_(2)O_(7-x)(x=-0.07-0.45)magneto-optical ceramics were fabricated by solid-state reactive sintering in vacuum combined with hot isostatic pressing(HIP)posttreatment without any sintering aids.The phase composition,densification process,microstructure,optical transmittance,and Verdet constant of Tb_(2)(Hf_(1-x)Tb_(x))_(2)O_(7-x)ceramics were investigated.The in-line transmittance of(Tb_(0.93)Hf_(0.04))_(2)Hf_(2)O_(7.07)ceramics with a thickness of 2.0 mm reaches 74.6%at 1064 nm.The Verdet constant of Tb_(2)(Hf_(1-x)Tb_(x))_(2)O_(7-x)ceramics is-153.4,-155.8,and-181.2 rad/(T-m)at the wavelength of 633 nm when x=-0.07,0,and 0.1,respectively.The Verdet constant increases with the increase of Tb content,and these values are higher than that of the commercial Tb_(3)Ga_(5)O_(12) crystal,indicating that non-stoichiometric Tb_(2)(Hf_(1-x)Tb_(x))_(2)O_(7-x)ceramics have a great potential for the application in Faraday isolators.
文摘Heavy-metal-oxide (HMO) glasses attract much interest in many applications such as Faraday rotators, current sensors, etc., in the area of magneto-optic effects due to their unique magnetic-optical property, high refractive index and other interesting properties. However, during the melt-quenching process of these glasses, the high corrosive nature of the melt to the crucibles makes the fabrication of HMO glasses complicated and the properties of the obtained glasses show strong dependence on the crucible materials. Literatures reported that the gold and platinum crucibles are not suitable due to their contamination to the melt glasses, ceramic crucible was considered suitable for the melting of HMO glasses. In this work, magnetic-optical glasses within the system of PbO-Bi2O3-B2O3 have been prepared using different kinds of ceramic crucibles for the aim of finding the most suitable crucible for melting HMO glasses. The glass properties in terms of Verdet constant, thermal stability and UV-Vis-IR transmittance in function of different crucibles were studied and reported. It was found that the same batch of glasses prepared under same conditions (melting temperature, melting time and annealing process), but in different ceramic crucibles (coded as C1, C2 and C3) showed significant difference in properties such as glass forming ability, thermal stability, optical absorption in UV-Vis-IR and Verdet constant (0.0812 - 0.1483 min/G.cm). The ceramic crucible made of 25%Al2O3 and 75%SiO2 (C2) was found to be the most suitable for PbO-Bi2O3-B2O3 glass preparation, compared with platinum, gold, C1 and C3. Glasses melted with C2 exhibit good performance in magneto and optical property, as well as good thermal stability.
文摘This paper summarizes the results of investigation of garnets Gd3Ga5O12 (GGG) on the basis of their optical activity. Dispersion of Verdet constant was measured in the visible light range and in a strong magnetic field. The applied technique, namely micropolarimetry, exhibits high resolution which corresponds to the type of polarization microscope used in the investigation.
文摘In this paper, we first theoretically report the magnetic and magneto-opticalproperties in paramagnetic media under high external magnetic field. Considering the action of theexternal magnetic Geld H_e and indirect exchange interaction H_v, the characteristic of the magneticsaturation and the property of the Faraday rotation to be nonlinear with external magnetic Geld arepresented in paramagnetic NdF_3. In terms of our theory, the indirect exchange interaction plays auimportant role in the magnetization M and the Faraday rotation θ in NdF_3 under high externalmagnetic Geld. The theory is in good agreement with experimental results. On the other hand, areasonable explanation for the temperature dependence of the ratio of the Verdet constant to themagnetic susceptibility V/x is obtained.
文摘建立了全光纤电流互感器（fiber-optical current transformer,FOCT）温度特性的数学模型。该模型充分考虑传感光纤的弯曲特性,结合光纤线性双折射的分布参数模型从本质上解释了温度对线性双折射的影响机理：由于传感环的弯曲性,温度变化会导致光纤横截面上的受力不对称,进而引起线性双折射;单位长度光纤的线性双折射相位差与温度变化量成正比,与光纤弯曲半径成反比。并结合光纤Verdet常数的温度特性综合量化了温度对FOCT的影响。采用COMSOL有限元分析方法实现光场、磁场、温度场、应力场的耦合并分析求解。仿真结果表明：双折射效应会使光波旋转角变小;光纤横截面上的应力差与温度变化量成正比,与光纤弯曲半径成反比;温度波动将引起线性双折射,进而使光波旋转角减小;结合Verdet常数得到了温度波动时FOCT的综合误差,与理论分析结果吻合。最后设计并搭建FOCT实验平台,进行线性度测试和温度循环测试。测试结果表明：实验误差与理论误差变化趋势基本一致;温度波动越大,FOCT误差漂移越严重,必须采取补偿措施,故提出一系列改善FOCT温度稳定性的方法。仿真与实验结果验证了理论分析的正确性。
