Development of Magnetooptical Plastic Fiber

本文介绍了一种利用具有磁光活性的Bi-YIG纳米粒子分散光学塑料纤维制成的电流传感器。采用共沉淀法和热处理法制备了双yig纳米颗粒。采用MMA作为基质，PMMA作为基质中的分散剂。随着Bi-YIG颗粒在光纤中的体积分数的增加，光纤的光吸收系数和饱和法拉第旋转、Veldet常数等磁光特性均有所增加。在优化的光纤长度和体积分数条件下，电流传感器最重要的参数Veldet常数是稀土掺杂玻璃的10倍。优选的光源波长为520 nm。Bi-YIG颗粒的分散性改善了磁光性能。为了改善共沉淀的分散性，即提高磨矿过程中的可磨性，试验了两种共沉淀添加剂。一种是NaOH溶液，另一种是硫酸铵。NaOH溶液的加入降低了结晶温度，使磨矿后的颗粒变小。TEM观察表明，在NaOH和硫酸铵共沉淀法下，粒径为20 ~ 40 nm的Bi-YIG颗粒分散良好，而在常规工艺下则存在混凝现象。色散性的差异导致吸收系数的降低和法拉第旋转的增加。最高评价值为4.8，达到了传统评价值的2倍以上。

This report describes a current sensor using Bi-YIG nanoparticle-dispersed optical prastic fiber with magnetooptical activity. Bi-YIG nanoparticles were prepared by coprecipitation followed by heat treatment. MMA was used for the matrix and PMMA was used for a dispersion agent in the matrix. Both optical absorption coefficient and magnetooptical properties such as saturation Faraday rotation and Veldet constant increased with increasing the volume fraction of the Bi-YIG particle in the fiber. Under the optimized conditions of the fiber length and the volume fraction the Veldet constant, which is the most important parameter for the current sensor, was 10 times as high as rare-earth doped glass. The most preferable wavelength of the optical source was 520 nm.Dispersability of the Bi-YIG particles improves the magnetooptical properties. Two additives for the coprecipitation were tried to improve the dispersibility, in other words, to improve grindability during the milling process. One was NaOH solution, and the other was ammonium sulfate. Adding NaOH solution decreased the crystallization temperature, leading to smaller particles after the milling process. TEM observation revealed that the Bi-YIG particles with the size of 20-40 nm were well dispersed in the case of the coprecipitation using NaOH and ammonium sulfate while coagulations exist in the case of the conventional process. The difference in the dispersibility led to the reduction in the absorption coefficient and the increase in the Faraday rotation. The maximum value of figure of merit reached 4.8, which is twice or higher than the conventional one.