Light Travels More Slowly Through Strongly Scattering Materials
DOI: 10.1063/1.2810133
We expect light to travel through a medium at a rate given by the speed of light in a vacuum divided by the average index of refraction of the material. But a recent experiment performed in the Netherlands indicates that in some strongly scattering materials it may actually take light five to ten times longer to traverse a sample than one would expect from this simple formula for the phase velocity. It appears that the light resonates for a while with the dielectric microspheres of which the material is made so the light takes longer to travel through the sample. This result challenges some assumptions made in the analysis of data from light scattering experiments, especially searches for localized light.
