The studies were made on the preparation processes of the rare earth metal and alloy target materials and their characterization. In this work the rare earth metals were prepared by electrolysis of the oxide in molten...The studies were made on the preparation processes of the rare earth metal and alloy target materials and their characterization. In this work the rare earth metals were prepared by electrolysis of the oxide in molten salt for Nd metal and metallothermic reduction of the fluorides for Gd, Tb, Dy metals. After vacuum refining and distillation purification these rare earth metals were used for manufacturing the element targets, mosaic targets and as the starting materials of preparing the rare earth-transition metal (RE-TM) alloy targets. The four kinds of Dy-FeCo, NdDy-FeCo, Tb-FeCo and GdTb-FeCo alloy targets with diameter of 100 mm and thickness of 3 mm were prepared using powder metallurgical technique. The oxygen content and microstructure of the prepared RE-TM cast alloys and sintered targets were analyzed. The features and requirements of the RE-TM alloy sputtering target materials were also discussed.展开更多
The novel Bi-substituted rare-earth iron garnet films were grown by the modified liquid phase epitaxy （LPE） technique for use as a 45° Faraday rotator in optical isolators.First,single crystals of Y3Fe5O12 （YI...The novel Bi-substituted rare-earth iron garnet films were grown by the modified liquid phase epitaxy （LPE） technique for use as a 45° Faraday rotator in optical isolators.First,single crystals of Y3Fe5O12 （YIG）,with a lattice constant of 1.237 8 nm,were grown by means of the Czochralski method.Using the seed crystal of YIG instead of the conventional non-magnetic garnet of Gd3Ga5O12 （GGG） as a substrate,a film of BiYbIG was grown by means of the LPE method from Bi2O3-B2O3 fluxes.The structural,magnetic and magneto-optical properties of BiYbIG LPE film/YIG crystal composite have been investigated using directional X-ray diffraction （XRD）,electron probe microanalysis （EPMA）,vibrating sample magnetometer （VMS） and near-infrared transmission spectrometry.The saturation magnetization 4πMs has been estimated to be about 1.2×106 A/m.The Faraday rotation spectrum was measured by the method of rotating analyzer ellipsometry （RAE） with the wavelength varied from 800 nm to 1 700 nm.The resultant Bi0.37Yb2.63Fe5O12 LPE film/YIG crystal composite showed an increased Faraday rotation coefficient due to doping Bi3+ ions into the dodecahedral sites of the magnetic garnet without increasing absorption loss,therefore a good magneto-optic figure of merit,defined by the ratio of Faraday rotation and optical absorption loss,has been achieved of 21.5 and 30.2 （°）/dB at 1 300 and 1 550 nm wavelengths respectively and room temperature. Since Yb3+ and Y3+ ions provide the opposite contribution to the wideband and temperature characteristics of Faraday rotation,the values of Faraday rotation wavelength and temperature coefficients were reduced to 0.06 %/nm and 0.007 （°）/℃ at 1 550 nm wavelength, respectively.展开更多
Faraday isolators can prevent the front-end system from disturbance and damage caused by a back-reflected beam,so they are important elements in laser systems.As magneto-optical materials are the most important compon...Faraday isolators can prevent the front-end system from disturbance and damage caused by a back-reflected beam,so they are important elements in laser systems.As magneto-optical materials are the most important component in Faraday isolators,the studies on magneto-optical materials have attracted much attention these years.Tb_(3)Al_(5)O_(12)(TAG)ceramics are considered to be one of the most promising magneto-optical materials for visible to near-infrared wavelength band application because of their outstanding comprehensive magneto-optical performance.However,the optical quality of TAG ceramics needs further optimization to meet the application requirements.In this work,high optical quality(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)(x=0,0.05,0.1,0.2,and 0.3)magneto-optical ceramics were fabricated successfully by solid-state reaction sintering combined with hot isostatic pressing(HIP)post-treatment.All the ceramics obtained showed a single garnet phase for different values of x in the range studied.The addition of Y_(2)O_(3) was found to suppress the secondary phase and improve optical quality significantly.The ceramic samples obtained had clear grain boundaries and possessed the in-line transmittance values of 82.9%at 1064 nm and 82.2%at 633 nm,respectively.The Verdet constants of(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)ceramics with x=0,0.05,0.1,0.2,and 0.3 were−188.1,−175.4,−168.5,−143.0,and−119.9 rad/(T·m),respectively.The thermal conductivity of TAG ceramics was found to be 5.23 W/(m·K)at 25℃,and when 20%Y was substituted in place of Tb,the thermal conductivity decreased by only 9.4%.展开更多
Fe-X-Ni(X=Cr,W and V)combinatorial thin-film(∼100 nm thick)materials chips covering the full composition range of ternary systems were fabricated.The crystal structure distribution was mapped by micro-beam X-ray diff...Fe-X-Ni(X=Cr,W and V)combinatorial thin-film(∼100 nm thick)materials chips covering the full composition range of ternary systems were fabricated.The crystal structure distribution was mapped by micro-beam X-ray diffractometers(XRD)and the magnetic hysteresis loops over the chip were characterized by a high-throughput magneto-optical Kerr effect(HT-MOKE)system to establish the composition-phase-magnetic properties relationships.The results showed that saturation magnetization for all systems has a strong dependency on alloying composition,and decreases with increasing dopped elements content as a general trend.Although the trend of saturation magnetization in bulk is in good agreement with that from thin films,all bulk samples show almost no coercivity,attributable to the much smaller grain size,and stronger texture in thin-film samples.Comparing the Fe-X-Ni systems under a similar condition,in the out-of-plane,Cr alloying obtained the largest coercivity(∼400 mT)followed by W alloying(∼300 mT)and then V alloying(∼200 mT).We suggest that alloying with different elements leads to the diverse orientation and crystallinity of the fcc phase resulting in different magnetic properties.Meanwhile,the effect of heat treatment on magnetic properties indicates that saturation magnetization is more closely related to the duration of heat treatment.展开更多
Faraday effect measurements of holmium oxide(Ho_2O_3) ceramics-based magneto-optical materials, highly potential material candidates for high-energy laser Faraday isolators, are presented in this paper. Temperature de...Faraday effect measurements of holmium oxide(Ho_2O_3) ceramics-based magneto-optical materials, highly potential material candidates for high-energy laser Faraday isolators, are presented in this paper. Temperature dependence of the Verdet constant of nondoped Ho_2O_3 ceramics was measured for temperatures 15–305 K at 1.064 μm wavelength.The Verdet constant dispersion for wavelengths 0.5–1 μm and 1.064 μm was measured for both nondoped Ho_2O_3 ceramics and Ho_2O_3 ceramics doped with terbium Tb3+(0.2 at. %) and cerium Ce3+(0.1 at. %) ions. The results suggest that the relatively low level of doping of Ho_2O_3 with these ions has no significant boosting impact on the Faraday effect. Therefore, other compositions of Ho_2O_3 ceramics-based magneto-optical materials, as well as various doping concentrations, should be further examined.展开更多
The ion substitution characteristics of Y3＋-doped （Tb0.sY0.2）3A15012 transparent ceramics synthesized by a solid-state reaction and vacuum sintering are investigated. The sample sintered at 1 680℃ exhibits the bes...The ion substitution characteristics of Y3＋-doped （Tb0.sY0.2）3A15012 transparent ceramics synthesized by a solid-state reaction and vacuum sintering are investigated. The sample sintered at 1 680℃ exhibits the best optical properties, yielding a transmittance 〉75% from 900 to 1 600 nm. The Verdet constant of this sample at 632.8 nm is -108.79 rad.T-l.m-1. X-ray diffraction （XRD） results show that all of the samples have a pure garnet crystal structure without secondary phases. The microstructure of the samples reveals homogeneous grain sizes that averages 〈10μm.展开更多
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
The polarization of a D-shaped fiber is modulated after immersing it in magnetic fluid(MF)and applying a magnetic field.Theoretical analysis predicts that magneto-optical dichroism of MF plays a key role in light pola...The polarization of a D-shaped fiber is modulated after immersing it in magnetic fluid(MF)and applying a magnetic field.Theoretical analysis predicts that magneto-optical dichroism of MF plays a key role in light polarization modulation.During light polarization modulation,the evanescent wave polarized parallel to the magnetic field has greater loss than its orthogonal component.Light polarization of a D-shaped fiber with a wide polished surface can be modulated easily.High concentration MF and a large magnetic field all have great ability to modulate light polarization.展开更多
The GdFeCo and NdGdFeCo thin films were prepared by sputtering, and their hysteresis loops, the temperature dependence of the saturation magnetization Ms and the magneto-optical Kerr spectrum in the visible light rang...The GdFeCo and NdGdFeCo thin films were prepared by sputtering, and their hysteresis loops, the temperature dependence of the saturation magnetization Ms and the magneto-optical Kerr spectrum in the visible light range were measured. By studying the effects of light rare earth element Nd doping on the magneto-optical Kerr rotation angle of GdFeCo thin films, it is found that proper Nd additives in GdFeCo films could enhance Kerr rotation at short wavelengths. So it could be better medium used as the readout layer of center aperture detection magnetically induced super resolution （CAD-MSR）.展开更多
The novel bismuth-substituted rare earth iron garnet films were grown by the modified liquid phase epitaxy (LPE) technique for use as a 45° faraday rotator in optical isolators. First,single crystals of Y_3Fe_5O_...The novel bismuth-substituted rare earth iron garnet films were grown by the modified liquid phase epitaxy (LPE) technique for use as a 45° faraday rotator in optical isolators. First,single crystals of Y_3Fe_5O_(12) (YIG),with a lattice constant of 1.2378 nm,were grown by means of the Czochralski method. Using YIG instead of the conventional non-magnetic garnet of Gd_3Ga_5O_(12) (GGG) as a substrate,a film of BiYbIG was grown by means of the LPE method from Bi_2O_3-B_2O_3 fluxes. The structural,magnetic and magneto-optical properties of BiYbIG LPE film/YIG crystal composite were investigated using X-ray diffraction (XRD),electron probe microanalysis (EPMA),vibrating sample magnetometry (VMS) and near-infrared transmission spectrometry. The saturation magnetization 4π M _s was estimated to be about 1200 G. The Faraday rotation spectrum was measured by the method of rotating analyzer ellipsometry (RAE) with the wavelength varied from 800 to 1700 nm. The resultant Bi_(0.37)Yb_(2.63)Fe_5O_(12) LPE film/YIG crystal composite shows an increased Faraday rotation coefficient due to doping Bi (3+) ions on the dodecahedral sites of the magnetic garnet without increasing absorption loss,therefore a good magneto-optic figure of merit,defined by the ratio of Faraday rotation and optical absorption loss,can achieved of 21.5 and 30.2 °/dB at 1300 and 1550 nm wavelengths respectively at room temperature. Since Yb (3+) ions and Y (3+) ions provide the opposite contributes to the wideband and temperature characteristics of Faraday rotation,the values of Faraday rotation wavelength and temperature coefficients are reduced to 0.06%/nm and 0 007 °·℃ (-1) at 1550 nm wavelength,respectively.展开更多
Interactions between light and magnetic matter attracted great attention lately due to their potential applications in nanophotonics,spintronics,and high-accuracy sensing.Here,we grew bismuth quantum dots(Bi–QDs)with...Interactions between light and magnetic matter attracted great attention lately due to their potential applications in nanophotonics,spintronics,and high-accuracy sensing.Here,we grew bismuth quantum dots(Bi–QDs)with strong spin–orbit coupling on a magnetic insulator yttrium iron garnet(YIG)via molecular beam epitaxy.The YIG/Bi–QDs material shows an enhanced magneto-optical Kerr rotation up to 130%compared with that of a bare YIG film.The Bi–QDs were also introduced onto a lutetium–bismuth co-doped YIG film to form a hybrid system with remarkably enhanced Kerr rotation(from 1626 to 2341 mdeg).Ferromagnetic resonance measurements showed an increased effective magnetization as well as interfacial spin–orbit field in the YIG/Bi–QD heterostructures.Localized plasmons were mapped using electron energy loss spectroscopy with high spatial resolution,revealing enhanced plasmon intensity at both the Bi–QD surface and YIG/Bi–QD interface.Introducing Bi-QDs onto the YIG film enhanced Kerr rotation owing to the attenuated optical reflection and increased effective magnetization.The Bi–QDenhanced magneto-optical effect enables development of efficient nanoscale light switching,spintronics,and even plasmonic nano-antennas.展开更多
We experimentally fabricate a non-spherical Ag and Co surface-enhanced Raman scattering（SERS） substrate, which not only retains the metallic plasmon resonant effect, but also possesses the magnetic field controllabl...We experimentally fabricate a non-spherical Ag and Co surface-enhanced Raman scattering（SERS） substrate, which not only retains the metallic plasmon resonant effect, but also possesses the magnetic field controllable characteristics.Raman detections are carried out with the test crystal violet（CV） and rhodamine 6G（R6G） molecules with the initiation of different magnitudes of external magnetic field. Experimental results indicate that our prepared substrate shows a higher SERS activity and magnetic controllability, where non-spherical Ag nanoparticles are driven to aggregate effectively by the magnetized Co and plenty of hot-spots are built around the metallic Ag nanoparticles, thereby leading to the enhancement of local electromagnetic field. Moreover, when the external magnetic field is increased, our prepared substrate demonstrates excellent SERS enhancement. With the 2500 Gs and 3500 Gs（1 Gs = 10^（-4）T） magnetic fields, SERS signal can also be obtained with the detection limit lowering down to 10^（-9）M. These results indicate that our proposed magnetic field controlled substrate enables us to freely achieve the enhanced and controllable SERS effect, which can be widely used in the optical sensing, single molecule detection and bio-medical applications.展开更多
基金Former the Ministry of Metallurgical Industry of China (BJ95-06-01)
文摘The studies were made on the preparation processes of the rare earth metal and alloy target materials and their characterization. In this work the rare earth metals were prepared by electrolysis of the oxide in molten salt for Nd metal and metallothermic reduction of the fluorides for Gd, Tb, Dy metals. After vacuum refining and distillation purification these rare earth metals were used for manufacturing the element targets, mosaic targets and as the starting materials of preparing the rare earth-transition metal (RE-TM) alloy targets. The four kinds of Dy-FeCo, NdDy-FeCo, Tb-FeCo and GdTb-FeCo alloy targets with diameter of 100 mm and thickness of 3 mm were prepared using powder metallurgical technique. The oxygen content and microstructure of the prepared RE-TM cast alloys and sintered targets were analyzed. The features and requirements of the RE-TM alloy sputtering target materials were also discussed.
基金Supported by the National Natural Science Foundation of China(61774130,11474248,61790581,51973070)the Ph.D.Pro⁃grams Foundation of Ministry of Education of China(20105303120002)National Key Technology Research and Development Program of the Ministry of Sci⁃ence and Technology of China(2018YFA0209101).
文摘The novel Bi-substituted rare-earth iron garnet films were grown by the modified liquid phase epitaxy （LPE） technique for use as a 45° Faraday rotator in optical isolators.First,single crystals of Y3Fe5O12 （YIG）,with a lattice constant of 1.237 8 nm,were grown by means of the Czochralski method.Using the seed crystal of YIG instead of the conventional non-magnetic garnet of Gd3Ga5O12 （GGG） as a substrate,a film of BiYbIG was grown by means of the LPE method from Bi2O3-B2O3 fluxes.The structural,magnetic and magneto-optical properties of BiYbIG LPE film/YIG crystal composite have been investigated using directional X-ray diffraction （XRD）,electron probe microanalysis （EPMA）,vibrating sample magnetometer （VMS） and near-infrared transmission spectrometry.The saturation magnetization 4πMs has been estimated to be about 1.2×106 A/m.The Faraday rotation spectrum was measured by the method of rotating analyzer ellipsometry （RAE） with the wavelength varied from 800 nm to 1 700 nm.The resultant Bi0.37Yb2.63Fe5O12 LPE film/YIG crystal composite showed an increased Faraday rotation coefficient due to doping Bi3+ ions into the dodecahedral sites of the magnetic garnet without increasing absorption loss,therefore a good magneto-optic figure of merit,defined by the ratio of Faraday rotation and optical absorption loss,has been achieved of 21.5 and 30.2 （°）/dB at 1 300 and 1 550 nm wavelengths respectively and room temperature. Since Yb3+ and Y3+ ions provide the opposite contribution to the wideband and temperature characteristics of Faraday rotation,the values of Faraday rotation wavelength and temperature coefficients were reduced to 0.06 %/nm and 0.007 （°）/℃ at 1 550 nm wavelength, respectively.
基金the National Key R&D Program of China(Nos.2021YFE0104800 and 2023YFB3812000)the General Project of Shanghai Natural Science Foundation(No.22ZR1471500)+2 种基金the International Partnership Program of Chinese Academy of Sciences(No.121631KYSB20200039)the International Cooperation Project of Shanghai Science and Technology Commission(No.20520750200)and National Center for Research and Development(Contract No.WPC2/1/SCAPOL/2021).Partial work was also financially supported by the Hengdian Group.
文摘Faraday isolators can prevent the front-end system from disturbance and damage caused by a back-reflected beam,so they are important elements in laser systems.As magneto-optical materials are the most important component in Faraday isolators,the studies on magneto-optical materials have attracted much attention these years.Tb_(3)Al_(5)O_(12)(TAG)ceramics are considered to be one of the most promising magneto-optical materials for visible to near-infrared wavelength band application because of their outstanding comprehensive magneto-optical performance.However,the optical quality of TAG ceramics needs further optimization to meet the application requirements.In this work,high optical quality(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)(x=0,0.05,0.1,0.2,and 0.3)magneto-optical ceramics were fabricated successfully by solid-state reaction sintering combined with hot isostatic pressing(HIP)post-treatment.All the ceramics obtained showed a single garnet phase for different values of x in the range studied.The addition of Y_(2)O_(3) was found to suppress the secondary phase and improve optical quality significantly.The ceramic samples obtained had clear grain boundaries and possessed the in-line transmittance values of 82.9%at 1064 nm and 82.2%at 633 nm,respectively.The Verdet constants of(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)ceramics with x=0,0.05,0.1,0.2,and 0.3 were−188.1,−175.4,−168.5,−143.0,and−119.9 rad/(T·m),respectively.The thermal conductivity of TAG ceramics was found to be 5.23 W/(m·K)at 25℃,and when 20%Y was substituted in place of Tb,the thermal conductivity decreased by only 9.4%.
基金We are grateful for the financial support from the National Key Research and Development Program of China(Grant Nos.2021YFB3702102 and 2017YFB0701900)the Major Science and Technology Project of Yunnan Province“Genome Engineering of Rare and Precious Metal Materials in Yunnan Province(Phase One 2020)"(Grant No.202002AB080001-1)Boyue Instruments(Shanghai)Co.,Ltd for support of m-XRF is also acknowledged。
文摘Fe-X-Ni(X=Cr,W and V)combinatorial thin-film(∼100 nm thick)materials chips covering the full composition range of ternary systems were fabricated.The crystal structure distribution was mapped by micro-beam X-ray diffractometers(XRD)and the magnetic hysteresis loops over the chip were characterized by a high-throughput magneto-optical Kerr effect(HT-MOKE)system to establish the composition-phase-magnetic properties relationships.The results showed that saturation magnetization for all systems has a strong dependency on alloying composition,and decreases with increasing dopped elements content as a general trend.Although the trend of saturation magnetization in bulk is in good agreement with that from thin films,all bulk samples show almost no coercivity,attributable to the much smaller grain size,and stronger texture in thin-film samples.Comparing the Fe-X-Ni systems under a similar condition,in the out-of-plane,Cr alloying obtained the largest coercivity(∼400 mT)followed by W alloying(∼300 mT)and then V alloying(∼200 mT).We suggest that alloying with different elements leads to the diverse orientation and crystallinity of the fcc phase resulting in different magnetic properties.Meanwhile,the effect of heat treatment on magnetic properties indicates that saturation magnetization is more closely related to the duration of heat treatment.
基金supported by JSPS KAKENHI (Grant No. 15KK0245)the support and under the auspices of the National Institute for Fusion Science (KEIN1608)+3 种基金co-financed by the European Regional Development Fundthe state budget of the Czech Republic (project Hi LASE Co E: Grant No. CZ.02.1.010.00.015 0060000674)by the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 739573supported by the Ministry of Education, Youth and Sports of the Czech Republic (Programmes NPU I Project No. LO1602, and Large Research Infrastructure Project No. LM2015086)
文摘Faraday effect measurements of holmium oxide(Ho_2O_3) ceramics-based magneto-optical materials, highly potential material candidates for high-energy laser Faraday isolators, are presented in this paper. Temperature dependence of the Verdet constant of nondoped Ho_2O_3 ceramics was measured for temperatures 15–305 K at 1.064 μm wavelength.The Verdet constant dispersion for wavelengths 0.5–1 μm and 1.064 μm was measured for both nondoped Ho_2O_3 ceramics and Ho_2O_3 ceramics doped with terbium Tb3+(0.2 at. %) and cerium Ce3+(0.1 at. %) ions. The results suggest that the relatively low level of doping of Ho_2O_3 with these ions has no significant boosting impact on the Faraday effect. Therefore, other compositions of Ho_2O_3 ceramics-based magneto-optical materials, as well as various doping concentrations, should be further examined.
基金supported by the National Natural Science Foundation of China(Nos.51172254 and 51202269)the Science and Technology Commission of Shanghai Municipality(No.10JC1415700)
文摘The ion substitution characteristics of Y3＋-doped （Tb0.sY0.2）3A15012 transparent ceramics synthesized by a solid-state reaction and vacuum sintering are investigated. The sample sintered at 1 680℃ exhibits the best optical properties, yielding a transmittance 〉75% from 900 to 1 600 nm. The Verdet constant of this sample at 632.8 nm is -108.79 rad.T-l.m-1. X-ray diffraction （XRD） results show that all of the samples have a pure garnet crystal structure without secondary phases. The microstructure of the samples reveals homogeneous grain sizes that averages 〈10μm.
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.
基金supported by the National Natural Science Foundation of China(Nos.61675115 and 11574178)the Shandong Provincial Natural Science Foundation(No.ZR2016JL005)。
文摘The polarization of a D-shaped fiber is modulated after immersing it in magnetic fluid(MF)and applying a magnetic field.Theoretical analysis predicts that magneto-optical dichroism of MF plays a key role in light polarization modulation.During light polarization modulation,the evanescent wave polarized parallel to the magnetic field has greater loss than its orthogonal component.Light polarization of a D-shaped fiber with a wide polished surface can be modulated easily.High concentration MF and a large magnetic field all have great ability to modulate light polarization.
文摘The GdFeCo and NdGdFeCo thin films were prepared by sputtering, and their hysteresis loops, the temperature dependence of the saturation magnetization Ms and the magneto-optical Kerr spectrum in the visible light range were measured. By studying the effects of light rare earth element Nd doping on the magneto-optical Kerr rotation angle of GdFeCo thin films, it is found that proper Nd additives in GdFeCo films could enhance Kerr rotation at short wavelengths. So it could be better medium used as the readout layer of center aperture detection magnetically induced super resolution （CAD-MSR）.
文摘The novel bismuth-substituted rare earth iron garnet films were grown by the modified liquid phase epitaxy (LPE) technique for use as a 45° faraday rotator in optical isolators. First,single crystals of Y_3Fe_5O_(12) (YIG),with a lattice constant of 1.2378 nm,were grown by means of the Czochralski method. Using YIG instead of the conventional non-magnetic garnet of Gd_3Ga_5O_(12) (GGG) as a substrate,a film of BiYbIG was grown by means of the LPE method from Bi_2O_3-B_2O_3 fluxes. The structural,magnetic and magneto-optical properties of BiYbIG LPE film/YIG crystal composite were investigated using X-ray diffraction (XRD),electron probe microanalysis (EPMA),vibrating sample magnetometry (VMS) and near-infrared transmission spectrometry. The saturation magnetization 4π M _s was estimated to be about 1200 G. The Faraday rotation spectrum was measured by the method of rotating analyzer ellipsometry (RAE) with the wavelength varied from 800 to 1700 nm. The resultant Bi_(0.37)Yb_(2.63)Fe_5O_(12) LPE film/YIG crystal composite shows an increased Faraday rotation coefficient due to doping Bi (3+) ions on the dodecahedral sites of the magnetic garnet without increasing absorption loss,therefore a good magneto-optic figure of merit,defined by the ratio of Faraday rotation and optical absorption loss,can achieved of 21.5 and 30.2 °/dB at 1300 and 1550 nm wavelengths respectively at room temperature. Since Yb (3+) ions and Y (3+) ions provide the opposite contributes to the wideband and temperature characteristics of Faraday rotation,the values of Faraday rotation wavelength and temperature coefficients are reduced to 0.06%/nm and 0 007 °·℃ (-1) at 1550 nm wavelength,respectively.
基金supported financially by the National Natural Science Foundation of China(Nos.51702042,61734002,61571079 and 51672007)the National Key Research and Development Plan(Nos.2016YFA0300801 and 2016YFA0300804)。
文摘Interactions between light and magnetic matter attracted great attention lately due to their potential applications in nanophotonics,spintronics,and high-accuracy sensing.Here,we grew bismuth quantum dots(Bi–QDs)with strong spin–orbit coupling on a magnetic insulator yttrium iron garnet(YIG)via molecular beam epitaxy.The YIG/Bi–QDs material shows an enhanced magneto-optical Kerr rotation up to 130%compared with that of a bare YIG film.The Bi–QDs were also introduced onto a lutetium–bismuth co-doped YIG film to form a hybrid system with remarkably enhanced Kerr rotation(from 1626 to 2341 mdeg).Ferromagnetic resonance measurements showed an increased effective magnetization as well as interfacial spin–orbit field in the YIG/Bi–QD heterostructures.Localized plasmons were mapped using electron energy loss spectroscopy with high spatial resolution,revealing enhanced plasmon intensity at both the Bi–QD surface and YIG/Bi–QD interface.Introducing Bi-QDs onto the YIG film enhanced Kerr rotation owing to the attenuated optical reflection and increased effective magnetization.The Bi–QDenhanced magneto-optical effect enables development of efficient nanoscale light switching,spintronics,and even plasmonic nano-antennas.
基金Project supported by the Key Science and Technology Research Project of Henan Province,China(Grant No.162102210164)the Natural Science Foundation of Henan Educational Committee,China(Grant No.17A140002)+1 种基金the National Natural Science Foundations of China(Grant Nos.11574276,11404291,and11604079)the Program for Science&Technology Innovation Talents in Universities of Henan Province,China(Grant No.17HASTIT0)
文摘We experimentally fabricate a non-spherical Ag and Co surface-enhanced Raman scattering（SERS） substrate, which not only retains the metallic plasmon resonant effect, but also possesses the magnetic field controllable characteristics.Raman detections are carried out with the test crystal violet（CV） and rhodamine 6G（R6G） molecules with the initiation of different magnitudes of external magnetic field. Experimental results indicate that our prepared substrate shows a higher SERS activity and magnetic controllability, where non-spherical Ag nanoparticles are driven to aggregate effectively by the magnetized Co and plenty of hot-spots are built around the metallic Ag nanoparticles, thereby leading to the enhancement of local electromagnetic field. Moreover, when the external magnetic field is increased, our prepared substrate demonstrates excellent SERS enhancement. With the 2500 Gs and 3500 Gs（1 Gs = 10^（-4）T） magnetic fields, SERS signal can also be obtained with the detection limit lowering down to 10^（-9）M. These results indicate that our proposed magnetic field controlled substrate enables us to freely achieve the enhanced and controllable SERS effect, which can be widely used in the optical sensing, single molecule detection and bio-medical applications.
