A new phase zone plate with suppressed higher-order flux is proposed and optimum design calculations are made for Al. While the first-order collecting efficiency is equal to that of conventional Fresnel zone plates (˜10%), the ratio of the higher-order flux energy to the first-order energy can be suppressed to <10-3-10-6 in the 300-600-Å wavelength range.
© 1985 Optical Society of America
Hakaru Kyuragi and Tsuneo Urisu, "Higher-order suppressed phase zone plates," Appl. Opt. 24, 1139-1141 (1985)