In white light interferometry, the visibility of the fringes is direct
ly related to the optical path difference between the two interfering
beams. With a very short coherence length light source, the zero-order
interference fringe may be detected by a simple maximum intensity loc
ation while the reference mirror is shifted by a piezoelectric transdu
cer. We use this possibility for high-resolution profilometry. We disc
uss the maximum sampling distance, which guarantees a correct detectio
n, as a function of the self coherence function of the light source. A
practical configuration based on Mirau interferometric microscope obj
ective was built. The experimental results show the nanometric resolut
ion of this technique and its ability to profile surfaces with sharp s
lopes and deep holes. The application field of either heterodyne or co
nfocal profilometers may be extended by associating them with the prop
osed method.