Boas D A, Bizheva K K, Siegel A M
Opt Lett. 1998 Mar 1;23(5):319-21. doi: 10.1364/ol.23.000319.
Dynamic low-coherence interferometry was used to measure Brownian motion of submicrometer particles within highly scattering media. Strong rejection of multiply scattered light was obtained by combination of a coherence gate with a confocal microscope, thus allowing particle characterization methods generally reserved for optically dilute materials to be applied to optically concentrated suspensions. The Brownian diffusion coefficient of highly scattering media was determined with an accuracy better than 5%. Furthermore, we show that spatial variations in the Brownian diffusion coefficient can be imaged with an axial resolution determined by the coherence length of the light source (~30 mum) . The experiments also show broadening of the power spectrum as a function of depth into the sample, most likely as a result of detecting multiply scattered light.
动态低相干干涉测量法被用于测量高散射介质中亚微米级颗粒的布朗运动。通过将相干选通与共聚焦显微镜相结合，实现了对多次散射光的强抑制，从而使得通常仅适用于光学稀释材料的颗粒表征方法能够应用于光学浓缩悬浮液。高散射介质的布朗扩散系数测定精度优于5%。此外，我们还表明，布朗扩散系数的空间变化可以通过由光源相干长度（约30微米）确定的轴向分辨率进行成像。实验还表明，功率谱会随着样品深度的增加而展宽，这很可能是检测到多次散射光的结果。
