Abstract

Until recently abrupt boundaries between layers were considered to be a requirement tor the proper operation of multilayer interference filters. This requirement has changed with the introduction of rugate filters which have graded-index boundaries between layers. Although the rugate filter has heretofore been confined to the spectral regions where nonabsorbing layers are available, the idea can also be applied to LSMs for the VUV and soft x rays where the layers are absorbing. For this application both the index of refraction and extinction coefficient must be graded. Calculations made using profiles employed in rugate filter design as well as other profiles have shown good suppression of higher-order interference but somewhat reduced first-order reflections. Results of the calculations are shown and some speculations made as to how such a filter can be constructed.

© 1988 Optical Society of America