Reflecting at 30.4 and Antireflecting at 58.4 nm

Abstract

We investigated how antireflection (AR) using thin film interference can be achieved in the EUV for multilayer mirrors. This may not been much investigated since AR is not usually needed. AR is not as straightforward as in the visible and neighboring frequencies for several reasons. No materials are entirely transparent in the EUV (indeed materials commonly used in the visible are among the most opaque). The optical constants are not known as well (particularly for compounds), and the antireflection layers can decrease the desired reflection from the multilayer at the "called for" energy. Incorporation of impurities can also be a problem. Nevertheless AR has a role to play in some circumstances.