Calculation of the Diffraction Efficiency in the Problem of Designing Multilevel Diffraction Gratings

Modelling of diffraction gratings is an urgent problem due to the need for their use in thermonuclear fusion. The possibility of modeling diffraction gratings with higher diffraction efficiency allows the radiation power of laser facilities to be increased. To achieve this goal, spectral beam combining is used. The diffraction efficiency is calculated by methods of mathematical physics and mathematical modelling, as well as by numerical methods. The diffraction efficiency of gratings of different configurations has been calculated by the original sign change method. Calculations of the diffraction efficiency of the diffraction gratings with one and three thresholds per period have been compared. The discussed numerical examples of modeling gratings with a more complex configuration demonstrate the advantages of the proposed model for calculating the diffraction efficiency over the available algorithms.