Fringe formation with a cross-grating interferometer

Abstract

The interference pattern in a cross-grating interferometer is analyzed using first-order analysis. To this order, the fringes are found to be wavelength independent. With white light extended source illumination, the cross-gratinglike structure is localized in a plane disregarding the source position. It is also found that, with some constraint on the separation between cross gratings, the amplitude of a generalized cross grating can be imaged in monochromatic spatially incoherent light. By broadening the spectrum of the illuminating source, each four-beam set of equal paths would form its own cross-gratinglike structure.