Measurement of the magneto-optical correlation length in turbid media

In multiple light scattering media, magnetic field induced circular birefringence (Faraday effect) influences interference effects such as speckle pattern or coherent backscattering. It was predicted that in the diffusive regime the relevant correlation length with respect to the Faraday rotation l( small star, filled )(F) differs, in general, from the transport mean free path l( small star, filled ). We have experimentally verified the prediction that the ratio l( small star, filled )(F)/l( small star, filled ) equals 2 for Rayleigh scattering and decreases to 1 with increasing scatterer size. We also discuss the influence of the structure factor on l( small star, filled )(F).