Design of highly efficient wideband multilayer coated blazed gratings providing constant C_ff-factor or deviation...

The universal approach was originally developed to design wideband multilayer coated blazed gratings operating in the tender X-ray region (E = 2-3 keV), realizing different diffraction geometries including constant incidence angle, constant C_ff-factor, and constant deviation angle, while retaining high diffraction efficiency in a wide spectral range.The designed gratings coated by depth-graded Cr/C multilayer structures and operating in the -1^st diffraction order are demonstrated to provide the constant factor C_ff = 2.52 or the constant deviation angle ψ = 4.75° with the diffraction efficiency of 29% ± 2% or 17.5% ± 1.5%, respectively, throughout the 2-3 keV spectral range.