Noise-related resolution limit of dispersion measurements with white-light interferometers

This paper presents results of our detailed theoretical and experimental analysis of the relationship between the spectral resolution and the noise in the group-delay dispersion (GDD) data measured by scanning white-light interferometry. We demonstrate that the practically achievable spectral resolution is limited, because the standard deviation of GDD is proportional to the third power of inverse spectral resolution, and for a specified accuracy the required number of averages scales with the sixth power of inverse spectral resolution. The influence of experimental parameters such as spectral brightness, bandwidth of the light source, and detection noise is examined in detail.