OBSERVATION OF LIGHT-PROPAGATION IN VOLUME SCATTERERS WITH 10(11)-FOLD SLOW MOTION

An optical method is introduced for observation of temporally and spat ially resolved frames that show how light propagates in diffusely scat tering materials. The method permits videos with 100-fs resolution in time to be produced. The method utilizes short-coherence interferometr y. The source of information is the speckle contrast. The temporal and spatial evolution of the multiple scattering process is demonstrated for several biological and industrial samples. A major objective of th e method is to investigate the conditions for optimum coherence and op timum apertures to achieve high resolution in the short-coherence inte rferometry. One important result is that during the propagation a shar p photon horizon evolves, which is useful for the morphological analys is of volume scatterers. (C) 1996 Optical Society of America