Integral calculation method of the efficiencies of laminar stratified gratings

We present an integral calculation method of the efficiencies of laminar stratified gratings. By stratified grating, we mean a medium whose optical index varies with the depth. The calculation is applied to the Bragg-Fraunhofer optics recently developed for the X-UV optics. The results of the method are compared to modal or differential methods already implemented for lamellar multilayer amplitude gratings.