From controlling the shape of Talbot bands' visibility to improving the sensitivity decay with depth in FD-OCT

We present theoretical and experimental studies on the sensitivity variation versus optical path difference (OPD) in Fourier domain spectral interferometry using configurations which produce Talbot bands. Such configurations require that the two interfering beams use different parts of the diffraction grating in the interrogating spectrometer. We show that by manipulating the power distribution within the two interfering beams, the OPD value where maximum sensitivity is achieved can be conveniently tuned, as well as the sensitivity variation with OPD. Furthermore, creating a gap between the two beams leads to adjustment of the minimum detectable OPD value, while the widths of the beams determine the maximum detectable OPD value. These features cannot be explained by theoretical models involving spectrometer resolution elements only. Improvement in the sensitivity variation with depth is demonstrated experimentally.