Detection of hidden objects in tissue like phantoms by backscattered diffused light

We present both experimental data and theoretical calculations of near-IR light backscattered from tissue like phantoms with hidden objects. The experimental setup constitutes an innovative detection system with a set of optical fibers sticked into a 2 ps resolution streak-camera scanning the light reflected by the illuminated sample. The data show that small, mm- size objects can be detected up to 12 mm in depth from the illuminated surface. The theory, that solves exactly the diffusion equation and introduces the sample boundary conditions, is in excellent agreement with the data.