New method of short-coherence interferometry in human skin (in vivo) and in solid volume scatterers

We adapted a method, the 'coherence radar', that was originally developed for the precise measurement of surface topology, to measure bulk properties within strongly scattering media. The sensor is based on short-coherence- interferometry. It enables the 2D observation of light propagation in scattering media with a high temporal resolution. The measurements are carried out by observing photons that traveled form an entrance focus through the bulk of the sample, and back to the surface. The source of information is the speckle contrast. One important result is that during the propagation a sharp photon horizon evolves. This photon horizon can be used for the detection on inhomogeneities in the scattering properties. In solid samples we measured absorbing obstacles with a depth of 320 micrometers and a depth uncertainty of < 5 percent. The measuring time is about 30 seconds. The observation of the photon horizon can also be realized in 'life' volume scatterers with moving scattering particles. First in vivo measurements of human skin have been successful.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.