磁光Bragg器件的不均匀偏置磁场分析

Analysis on Nonuniform Bias Magnetic Field of Magneto-optic Bragg Cells

讨论了缓变不均匀偏磁场对静磁波振幅，进而对磁光Ｂｒａｇｇ器件衍射效率的 影响，给出了设计适当不均匀场的理论依据。分析表明，适当的不均匀场可以明显提高静磁 波振幅，提高的幅度与该点场强以及激发静磁波处的场强有关，与不均匀静磁场在其它点的 具体分布无关。该结论对适当设计磁光Ｂｒａｇｇ器件的偏置磁场，提高其衍射性能等方面有指导 作用。

The dependence of the dynamic magnetization of magnetostahc waves(MSWs) and the diffraction efficiency of the MSW-based magneto-optic(MO) Bragg cells on the slightly nonuniform bias magnetic field is discussed in detail. The theorehcal basis for designing appropriate nonuniform bias magnetic field is provided in this paper. It is indicated by analysis that, the amplitude of MSW dynamic magnetization can greatly be enhanced under appropriately nonuniform bias magnetic field and the increment is dependent on the intensity of the nonuniform magnetic field at the site considered and that of the bias magnetic field to generate the MSWs, and independent on the specific profile of the nonuniform bias magnetic field in other places. The conclusion may help to appropriately design the bias magnetic field, and as a result the diffraction performance of the MSW based MO Bragg cells can be improved.