Two experiments to measure the size of microscopic dielectric spherical particles immersed in purified water with spheres of a nominal diameter 5.2 ± 0.15 μm have been carried out in order to revisit Mie scattering techniques. The first experiment uses a 1 mW helium-neon (He-Ne) laser with a wavelength of 632.8 nm, while the second one is carried out using a diode laser of 780.0 nm wavelength and a nominal power of 80 mW. The distribution of the scattered light intensity is recorded experimentally, and since the theoretical background has been known for several decades (see references), only a modest amount of theory is included. We considered the Mie scattering by a set of spheres of different diameters in our case with a distribution of sphere diameters with mean diameter 5.2 μm and standard deviation 0.15 μm. Our measured Mie scattering angular distribution accounts for the effect of the diameter distribution, which we assume to be a Gaussian distribution. Our results indicate that there is very good agreement between experiment and theoretical predictions. The technique we offer here is found to be useful to familiarize technicians who work in the areas of applied optics, such as chemistry, electronics, water contamination, and optical instruments with Mie scattering techniques, and who may not have a formal introduction to the electromagnetic theory. One specific area in which these techniques might be useful is the study of aerosols that may arise when naturally produced droplets from humans, such as those produced by coughing, sneezing, talking, and breathing, are present, as it happens in response to the Severe Acute Respiratory Syndrome Coronavirus 2, also known as SARS-CoV-2.

中文翻译：

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重新审视米氏散射：通过球形粒子分布研究电磁波的双色米氏散射

为了重新审视米氏散射技术，已经进行了两个实验来测量浸入纯净水中的微观介电球形颗粒的尺寸，其中球体的标称直径为 5.2 ± 0.15 μm。第一个实验使用波长为 632.8 nm 的 1 mW 氦氖 (He-Ne) 激光器，而第二个实验使用波长为 780.0 nm 的二极管激光器，标称功率为 80 mW。散射光强度的分布是通过实验记录的，并且由于几十年的理论背景已经为人所知（参见参考资料），因此只包括了少量的理论。在我们的案例中，我们考虑了一组不同直径球体的 Mie 散射，球体直径分布的平均直径为 5.2 μm，标准偏差为 0.15 μm。我们测量的米氏散射角分布考虑了直径分布的影响，我们假设它是高斯分布。我们的结果表明实验和理论预测之间有很好的一致性。我们在此提供的技术对于熟悉在应用光学领域工作的技术人员非常有用，例如化学、电子、水污染和具有米氏散射技术的光学仪器，并且可能没有正式介绍电磁理论。这些技术可能有用的一个特定领域是研究当人类自然产生的飞沫（例如咳嗽、打喷嚏、说话和呼吸产生的飞沫）存在时可能产生的气溶胶，