Optical profile determining apparatus and associated methods including the use of a plurality of wavelengths in the reference beam and a plurality of wavelengths in a reflective transit beam

An optical profile determining apparatus includes an optical detector and an optical source. The optical source generates a transmit beam including a plurality of wavelengths, and generates a reference beam including the plurality of wavelengths. Optical elements direct the transmit beam to a target, direct a resulting reflected transmit beam back from the target to the optical detector, and combine the reference beam with the reflected transmit beam so that a profile of the target is based upon fringe contrast produced by the plurality of wavelengths in the reference beam and the plurality of wavelengths in the reflected transmit beam.