光源的偏振态对动态光散射颗粒测量结果的影响

Effect of the polarization state of the laser in dynamic light scattering for particle sizing

研究了在动态光散射纳米颗粒测量中,光源的偏振态对测量结果的影响。采用了粒径为100nm、体积浓度为0.5%的标准颗粒作为样品,使He-Ne激光通过起偏器得到0°～180°方向的偏振光,测量了散射光强、偏振度和粒径测量值的变化,计算了相应的粒径均值偏差和标准差,并将这一结果与无偏振He-Ne激光入射进行了比较。结果表明,当入射光为线偏振光时,偏振方向垂直于散射面时测量效果最好;另一方面,由于颗粒系散射迭加造成的散射光偏振度降低,使线偏振光源与无偏振光源产生的散射光偏振度无明显差别,证明在测量中可以使用无偏振He-Ne激光代替。

In order to study the effect of the polarization state of the laser for particle sizing in dynamic light scattering, the sample particles which are 100nm in diameter and 0.5 % in concentration are prepared. The polarized light of 0° to 180° direction is obtained by the He-Ne laser through the polarizer. The intensity and polarization ratio and the particle size are measured, and the corresponding average, error, and standard deviation of the measurement value are calculated. Furthermore, the results are compared with those measured by non-polarized He-Ne laser. The experiment results indicate that, when the laser is linearly polarized light, the best measurement is acquired under the polarization direction perpendicular to the .scattering surface. On the other hand, the reduction of the degree of polarization of the scattering because of the superposition of the scattering particle resuits in no significant difference in the degree of polarization between linearly polarized light and non-polarized light, which can be used in the measurement with non-polarization He-Ne laser instead.