【摘要】 本文应用经典电磁场论,从 Lorentz 电子运动模型出发,结合有效场概念推导了磁光介质磁圆二向色性∈的色散关系,以及∈与有效场 H_i 和介质厚度 L 的关系。在正常色散区引入有效消光系数η概念,分析了∈与磁圆振双折射θ的相互关系。将推得的∈和θ表达式与用量子力学理论在双能级跃迁模型上得到的∈和θ表达式作了比较分析,阐述了线宽Γ和能级分裂△对∈和θ作用的微观机理。实验上测量了（BiTm）₃（FeGa）₅O₁₂磁光单晶薄膜的磁光旋转谱,以及∈、θ与 He、膜厚 h 的关系,并结合其吸收光谱作了相应分析。实验结果与理论分析符合较好。更多还原

【Abstract】 According to the Lorentz electron motion model and combined with the effective field concept,the dispersing relation of magnetic circular dichroism ε and the representation of ε to effective field H_j and thickness L of a sample are derived in this paper by means of the classical electromagnetic field theory.Also,the relation-ship of e and θ which stands for magnetic circular bireferigeuce is discussed by using the effective extinction coefficient in a normal dispersion region.The above results are analyzed by comparing with the expressions of ε and θ that are based on the double-transition model of quantum mechanics,and the micromechanism of the influences of linewidth L and energy level spliting ⊿ on e and θ are expounded. Experimentally,the spectra of magneto-optical rotation and the relationships of θ-H_?,ε-H_? and θ-2h,ε-2h of （BiTm）₃（FeGa）₅O₁₂ magneto-optical single crystal thin film are measured.At the same time,the absorption spectra are analyzed.The theoretical studies a conformed with the experimental results.更多还原