DIFFRACTION GRATING ILLUMINATED BY PARTIALLY COHERENT BEAM

A diffraction grating illuminated by partially coherent radiation has been investigated in the framework of scalar wave theory. The angular distribution of the light intensity behind the grating has been derive d, using the formalism of correlation theory in the space-frequency do main. The source of radiation has been assumed to be quasi-homogeneous . In contrast to the coherent case, the angular dependence of the inte nsity differs, in general, from the spectrum of the radiation. However , in most cases of practical interest this effect is negligibly small.