Duran-Ledezma Angel A, Jacinto-Méndez Damián, Rojas-Ochoa Luis F
Appl Opt. 2018 Jan 10;57(2):208-216. doi: 10.1364/AO.57.000208.
We present a combined experimental, theoretical, and numerical study of photon transport and microscopic dynamics in rigid and drying turbid thin films. Our setup is based in multispeckle diffusing wave spectroscopy and is adapted for frequency sweep of the illuminating source. We apply our approach to simultaneously monitor the changes in optical properties and microscopic dynamics of turbid thin films of rutile TiO powder dispersed in ethanol during the full drying process. Accordingly, we introduce an extension of the photon diffusion model for spectral speckle intensity correlations to account for system microscopic dynamics. We find that our results are well described by the model, where parameters required as the time-dependent sample thickness and transport mean free path are obtained from experiments. Furthermore, our findings are validated by numerical simulations of speckle dynamics based on the copula scheme. We consider that our scheme could be useful in time-resolved physical characterization of time-evolving turbid thin systems.
我们展示了一项关于刚性和干燥浑浊薄膜中光子传输和微观动力学的综合实验、理论和数值研究。我们的装置基于多散斑扩散波谱，并适用于照明源的频率扫描。我们应用该方法在整个干燥过程中同时监测分散在乙醇中的金红石TiO₂粉末浑浊薄膜的光学性质和微观动力学变化。相应地，我们引入了光子扩散模型的扩展，用于光谱散斑强度相关性，以考虑系统微观动力学。我们发现该模型能很好地描述我们的结果，其中作为随时间变化的样品厚度和输运平均自由程所需的参数是通过实验获得的。此外，我们的发现通过基于copula方案的散斑动力学数值模拟得到了验证。我们认为我们的方案可能有助于对随时间演变的浑浊薄系统进行时间分辨物理表征。
