Spatial-spectral interference is an effective way to characterize an unknown ultra-short pulse. The key of characterizing an unknown ultra-short pulse is to retrieve the dispersion. Considering that the spatial-spectral interference fringe is the equiphase line of different spectra in the space domain and that the phase difference between adjacent interferences is equal to 2π. ... https://parisnaturalfoodes.shop/product-category/nutri-b12/