Calculation of diffraction efficiency in the problem of designing multilevel diffraction gratings

The process of modelling diffraction gratings is an actual problem due to the great need for their use for the needs of thermonuclear fusion. It is necessary to model diffraction gratings with higher diffraction efficiency for solving such problems. It allows us to increase the radiation power of laser installations. The spectral beam combining is applied to achieve these goals. We use various numerical methods and mathematical modelling to solve these problems. Numerical examples demonstrate the possibility of modeling more complex diffraction grating configurations than previous algorithms allowed. A comparison is made of diffraction efficiency calculations for diffraction gratings with one and three thresholds per period. The results of comparison of calculations showed the effectiveness of the proposed algorithm.