Demonstration of tolerance to dispersion of master/slave interferometry
Adrian Bradu, Michael Maria, and Adrian Gh. Podoleanu
Master/Slave Interferometry (MSI) is a recently proposed Spectral Domain Interferometry (SDI) technique. MSI differs from the conventional Spectrometer based-SDI (Sp-SDI) or Swept source-SDI (SS-SDI) by switching the main mathematical operation from a Fast Fourier Transformation (FFT) to a Cross-Correlation between pre-recorded data called Masks and data collected from the sample to investigate. MSI principle also differs from conventional SDI by direct en-face image (C-scan) instead of transverse image (B-scan). MSI principle has been applied to typical eye imaging situation and provides similar results in term of sensitivity and axial resolution compare to state of the art Optical Coherence Tomography (OCT) system. In this paper, the effect of dispersion on MSI and FFT based techniques has been studied. Theoretical and experimental demonstration shown that accurate measurements under dispersive condition can only be achieved using MSI.
In order to demonstrate the MSI insensitivity to dispersion, we proposed a simple metrology experiment where we have investigated the thickness of a microscope cover slip under four different dispersive condition (unbalanced fiber length of 0, 0.5, 1.0 and 1.5 meter within the interferometer).
Fig 1. Averaged and standard deviation of measured thickness of a microscope cover slip under dispersive condition (length of unbalanced fiber in the interferometer).