Control of visibility profile in spectral low-coherence interferometry

It is demonstrated that, by obstructing half of one of the two beams from a low coherence interferometer before it is incident on the diffraction grating in a spectral interferometry setup, an asymmetric profile can be generated for the visibility of the channelled spectrum (V) with optical path difference (OPD). Together with a lateral shift of the beam, as inspired by Talbot bands studies, this can be used to optimise V(OPD). The model for the visibility of Talbot bands is improved by considering the spectrometer resolution and an improved Talbot band experiment is demonstrated. It is also shown that it is possible to obtain regions of no interference around zero OPD.