Biological materials probed by the temporal and angular profiles of the backscattered ultrafast laser pulses

Temporal and angular profiles of backscattered pulses are introduced as a practical, novel, and noninvasive technique to probe biological materials. The optical properties of these materials are quantitatively measured in terms of two scattering-length scales: the transport mean free path and the absorption length of the light. We show that these two scattering lengths can be directly determined from an analysis of the temporal or the angular profile of the backscattered pulse intensity. Experimental results for transient light backscattering from eye, heart, lung, and breast tissues, and from a tooth and a leaf, are presented.