Dual-band reflection from single-stack multilayer systems: a case study for the extreme ultraviolet and beyond

Single-stack multilayer systems with constant bilayer thickness are investigated numerically with the aim of producing multiple reflection peaks by using different orders of interference. That way, mirrors with peaks at harmonically spaced wavelength pairs are designed. Different combinations of harmonics, e.g., the 1 st and the 2 nd or the 3 rd and the 4 th , are selected by varying the thickness ratio of the individual layers in the bilayer. Bilayer materials showing high index contrast at both wavelengths are identified for the extreme ultraviolet and beyond. Results for ideal systems with sharp interfaces as well as for more realistic ones with diffuse interfaces are presented. Topic: Extreme ultraviolet spectroscopy