Achieving variation of the optical path length by a few millimeters at millisecond rates for imaging of turbid media and optical interferometry: a new technique

A new technique that offers very high stability and repeatability in varying the optical path length by a few millimeters at a millisecond rate is demonstrated. The technique is simply based on a rotating optical cube with parallel facets. The optical path length is varied at a nonlinear rate, and the data can be presented in the frequency or the spatial domain.