Corrections of the travelling-fringe period for the interference of aberrated beams

When laser beams are used for length measurements by interferometry and the realisation of the meter, they are approximated by plane waves. Hence, from the measured frequency, the dispersion relation of plane waves gives the wavelength in a vacuum and, consequently, the period of the interference signal. However, this relation does not hold exactly and the wavelength is not a well-defined quantity. Aberrations of the wavefront and intensity profile bias the phase accumulation and originate measurement errors. This paper gives the corrections for the period of the integrated interference of aberrated paraxial beams.