Design and fabrication of robust broadband extreme ultraviolet multilayers

Abstract

The random layer thickness variations can induce a great deformation of the experimental reflection of broadband extreme ultraviolet multilayer. In order to reduce this influence of random layer thickness fluctuations, the multiobjective genetic algorithm has been improved and used in the robust design of multilayer with a broad angular bandpass. The robust multilayer with a lower sensitivity to random thickness errors have been obtained and the corresponding multilayer mirrors were fabricated.The experimental results of robust Mo/Si multilayer with a wide angular band were presented and analyzed, and the advantage of robust multilayer design was demonstrated.

Design optimization of broadband extreme ultraviolet polarizer in high-dimensional objective space

“…Furthermore, an advanced optimization technique is very important for the design of multilayered coating in other wavelength range, [16] and multi-objective optimization is also needed in the designs of optical coatings. [17,18] Most recently, we introduced the multi-objective genetic algorithms (MOGA) in the design and fabrication of broadband EUV multilayer, [19,20] but the basic MOGA can not go forward to find optimal solutions when encountering a task with more than three objectives, especially many parameters need to be optimized.…”

Multiobjective optimization in design of broadband extreme ultraviolet multilayers

“…However, the multilayer design requires to optimize many parameters and the merit functions are complex, thus the solution space is quite large, and it is not easy to obtain the Pareto-optimal front. Up to now, MOGA has been used in the designs of broadband EUV multilayers with two optimized targets [12]. In this letter, we improved an MOGA and developed the MOGA with angle-based preference selection mechanism (MOGA-ANGLE), and then we combined these two algorithms and expanded them into the designs of EUV broadband multilayers with 3D objectives.…”