磁光晶体Bi-YIG的磁致退偏效应

建立了磁光晶体磁致偏振特性测试系统。对Bi YIG晶体样品在大范围磁场下的退偏现象进行了测试。结果表明,达到磁饱和或接近磁饱和时,Bi YIG晶体的偏振性能最优;达到磁饱和后,随着磁场的增强,出现了磁致退偏效应。根据实验结果分析了磁致退偏效应的产生机理,并说明了磁致圆二向色性及磁致线双折射是产生退偏的原因。

Depolarization effect of magneto-optic crystal Bi-YIG in adjustable magnetic field

The optical system is established in which the changes of polarization state for magneto-optic crystal can be measured. In this optical system, the depolarization effect in Bi-YIG crystal which often be used in optical isolator is measured in large variation range of adjustable magnetic field. The experiment result shows that polarization performance is best in Bi-YIG crystal when it reaches saturated magnetization. And the depolarization effect is occured when the intensity of magnetic field increases over saturation intensity. The principle for magnetic depolarization effect is also given according to the experimental result. The magnetic circle dichroism and magnetic linear birefringence is the reasons which cause depolarization effect.