Experimental determination of the intensity distribution across a source with a grating interferometer

An interferometric technique based on the use of a diffraction grating is used to recover the intensity distribution across a spatially incoherent planar source. Information about the source profile is obtained through measurements of visibility and position of the fringe pattern at transverse planes beyond the grating. Such quantities are shown to be independent of the wavelength of the radiation, so that broadband sources can be analysed without any spectral filtering. Experimental results are given.