Design of bifunctional XUV multilayer mirrors using a genetic algorithm

We designed multilayer mirrors for the IMAGE/Explorer mission that were intended to reflect well at 304 * and poorly at 584 *. The best designs utilized the novel materials U and Y _2 O _3 with Al or Si as spacer layers. The highest design reflectivities were obtained with aperiodic multilayers, although these were too hard to grow in practice. We found these novel designs using a genetic algorithm calling on a database of 43 promising materials with the freedom of aperiodic multilayer stacks.