Ballistic attenuation of low-coherence optical fields.

Using a novel experimental geometry, we measured the ballistic attenuation of low-coherence optical fields propagating in multiple-scattering media. The high dynamic range and the angular filtering capability permit detecting the ballistic component through random media thicker than 20 mean free paths. Owing to the accuracy of the technique, we observe deviations from the standard Lambert-Beer law that are induced by the broad incident optical spectrum. We discuss the significance of these observations, their dependence on the type of scattering, and several potential applications.