Abstract
The low coherence interferometry in Fourier space (FD-OCT) is a technique to measure distance with
typical values of dynamic range in the order of 3 mm and resolution below 10 microns. In this paper
we propose to combine the interferometric technique with a technique that measures distances
using astigmatic focus signal, allowing lead the resolution limit of less than 10 nm.
The experimental scheme shown armed with both techniques and experimental results in
displacement of a sample surface, controlled feedback system with a piezoelectric strain gauge which we have used as a reference system..