Design of multilayer mirrors for XUV applications using simulated annealing

Abstract
By combining previous multilayer optics design methods a multilayer mirror (MLM) optimisation programme has been developed to provide a versatile tool for MLM design for the XUV range. The programme uses a simulated annealing algorithm to avoid the design of suboptimal multilayered stacks. Investigations have been carried out on the influence of the computational sublayer thickness used in the computation and on the algorithm for reducing the simulated annealing temperature. The optimisation programme allows variation of the angle of incident radiation, the interface roughness and the number of différent materials within the MLM structure. The possibility of optimising the performance of the MLM using différent merit functions or reflectivity profiles has been implemented. Variation of the incidence angle allows the design of polarisers by optimising at the Brewster angle and ratios of R_s/R_p around 10 ³ are achieved for specific wavelengths. To select a specific line from a superimposed line and continuum spectrum a selective merit function is used. By maximising the ratio of the relevant line throughput to the continuum throughput, such MLM designs can be used to select a specific line from an électron impact or laser plasma source spectrum for microscopy or microbeam radiation experiments.