Rigorous integral method in application to computing diffraction on relief gratings working in wavelength range from microwaves to x ray

Application of rigorous integral method for computing the efficiency of arbitrary profile relief gratings used in all the optical spectral range is presented in this paper. The main progress of the method and the programs lays in numerical solution algorithm. In particular, an approximation of Green-function and its normal derivative is used providing a sufficient accuracy for common practice simultaneously with satisfactory computation time. There is a very important peculiarity of the algorithm, namely both distribution of points of collocation and choice of the number of terms in Green-function expansion are used. These characteristics are different for each special case: perfect conductivity, finite conductivity, transmission gratings and gratings for X-ray and XUV. Such programs can be used as a mathematical model to design and calculate complex multielement optical systems with diffraction gratings.