摘要
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.
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 Y_3Fe_5O_(12) (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 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 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 4πM_s has been estimated to be about 1.2×10~6 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 Bi_(0.37)Yb_(2.63)Fe_(5)O_(12) LPE film/YIG crystal composite showed an increased Faraday rotation coefficient due to doping Bi^(3+) 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 Yb^(3+) and Y^(3+) 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
NationalNaturalScienceFoundationofChina (6 9890 2 30 )
TeacherScientificResearchProjectofCityCollege
ZhejiangUniversity(J5 1 1 0 2 0 31 0 0 1 )
