Observation of mean path length invariance in light-scattering media

Abstract

Scattered light, it is all the same Materials can vary from transparent to opaque depending on the density of scatters within the medium. As light propagates through a material, intuition might suggest that the more scatters there are, the shorter the path along which the light can propagate. Savo et al. confirm a recent theoretical proposal that predicts that this is not the case. They shone light through a series of samples of varying scatterer density and found that the average path length that the light traveled was independent of the sample microstructure. This finding should also be applicable to acoustics and matter waves. Science , this issue p. 765