System for measuring length of optical path and Doppler shift for fixed path, uses low coherence light source and Mach-Zehnder interferometer

摘要

The system measures the optical differences between the reaction of normal skin to a beam of light and that of a skin tumor. The light from a non-coherent source (1) is split into a reference beam (2) and a measuring beam (3). The light reflected from the scattering medium, in this case, skin (4) and the reflected (6) reference beam are detected (5). The fact that light passes through differing media at differing speeds, produces a Doppler shift between the beams, which is measured.