Enhanced backscattering (EBS) otherwise known as coherent backscattering is a fascinating optical phenomenon that gives rise to the enhancement of light backscattering in random media in directions close to the backscattering. EBS originates from the weak localization of light in random medium leading to the constructive interference of photons traveling time-reversed paths. Our group was the first to report an experimental observation of an extension of EBS, enhanced backscattering with spatially low coherent illumination (LEBS). LEBS occurs when the spatial coherence length of illumination is smaller than the mean free path length of light in the medium. The use of low-coherent light makes it possible to easily record enhanced backscattering in weakly scattering media such as living tissue, which has not been previously possible. It also enables depth-resolved tissue spectroscopy. Our objective is to develop analytical and numerical models of LEBS in weakly-scattering media in general and biological tissue in particular.
