Diffuse Thickness as a Measure of Light Scattering

Abstract

The concept of diffuse thickness was developed as an alternative method of measuring the light scattering in diffusely reflecting samples. It is defined as the minimum thickness of a diffusely reflecting and transmitting material required to produce complete diffusion. A series of liquid samples with varying concentrations of a green dye differed in light scattering by as much as 7:1 and in reflectance by 8:1. Results showed the diffuse thickness to be independent of absorption. In addition, the diffuse thickness was used with reflectance data to compute an absorption coefficient that correlated linearly with dye concentration despite the differences in light scattering ( r = 0.99896). Additional data obtained with samples in which the scattering was varied by changing the proportion of two types of particles showed that a different mathematical procedure was required to obtain an equivalent correlation.