Determination of the scattering anisotropy with optical coherence tomography

In this work we demonstrate measurements with optical coherence tomography (OCT) of the scattering phase function in the backward direction and the scattering anisotropy parameter g. Measurements of the OCT attenuation coefficient and the backscattering amplitude are performed on calibrated polystyrene microspheres with a time-domain OCT system. From these measurements the phase function in the backward direction is determined. The measurements are described by the single scattering model and match Mie calculations very well. Measurements on Intralipid demonstrate the ability to determine the g of polydisperse samples and, for Intralipid, g = 0.35 ± 0.03 is measured, which is well in agreement with g from literature. These measurements are validated using the Intralipid particle size distribution determined from TEM measurements. Measurements of g and the scattering phase function in the backward direction can be used to monitor changes in backscattering, which can indicate morphological changes of the sample or act as contrast enhancement mechanism.