Opt Lett. 2013 Nov 15;38(22):4750-3. doi: 10.1364/OL.38.004750.
We present an angular-scattering optical method that is capable of measuring the mean size of scatterers in static ensembles within a field of view less than 20 μm in diameter. Using interferometry, the method overcomes the inability of intensity-based models to tolerate the large speckle grains associated with such small illumination areas. By first estimating each scatterer's location, the method can model between-scatterer interference as well as traditional single-particle Mie scattering. Direct angular-domain measurements provide finer angular resolution than digitally transformed image-plane recordings. This increases sensitivity to size-dependent scattering features, enabling more robust size estimates. The sensitivity of these angular-scattering measurements to various sizes of polystyrene beads is demonstrated. Interferometry also allows recovery of the full complex scattered field, including a size-dependent phase profile in the angular-scattering pattern.
我们提出了一种角散射光学方法，能够测量视场小于 20μm 直径的静态散射体的平均尺寸。该方法利用干涉测量法克服了基于强度的模型无法容忍与如此小的照明区域相关的大散斑颗粒的缺点。通过首先估计每个散射体的位置，该方法可以模拟散射体之间的干涉以及传统的单颗粒 Mie 散射。直接角域测量提供比数字转换后的像面记录更高的角分辨率。这增加了对尺寸相关散射特征的灵敏度，从而实现更稳健的尺寸估计。实验证明了这些角散射测量对各种尺寸的聚苯乙烯珠的灵敏度。干涉测量法还允许恢复完整的复散射场，包括角散射模式中的尺寸相关相位分布。
