Self-referenced method for optical path difference calibration in low-coherence interferometry.
A simple method for the calibration of optical path difference modulation in low-coherence interferometry is presented. Spectrally filtering a part of the detected interference signal results in a high-coherence signal that encodes the scan imperfections and permits their correction. The method is self-referenced in the sense that no secondary high-coherence light source is necessary. Using a spectrometer setup for spectral filtering allows for flexibility in both the choice of calibration wavelength and the maximum scan range. To demonstrate the method's usefulness, it is combined with a recently published digital spectral shaping technique to measure the thickness of a pellicle beam splitter with a white-light source.
Laubscher
M
M
Institute of Biomedical Imaging, Optics and Engineering, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland. markus.laubscher@epfl.ch
Froehly
L
L
Karamata
B
B
Salathé
R P
RP
Lasser
T
T
D002138:Calibration; D007368:Interferometry; D008962:Models, Theoretical; D012016:Reference Values; D013057:Spectrum Analysis