Abstract

In order to measure or to transform the polarization state in the soft x-ray region, we need a suitable quarter-wave plate. Kortright and Underwood^[1] have shown theoretically that the transmission type multilayer has a good potential for a quarter-wave plate in the soft x-ray region. They demonstrated as a good example, the Mo/Si multilayer which has a periodicity of 9.0 nm and 20 periods at the wavelength of 13.8 nm, has the retardation Δ_p-Δ_s=86°, the polarizance (T_s-T_p)/(T_s+T_p) =42% and the throughput for s-component of 39% at the incident angle of 39.7° measured from the sample normal. The best quarter-wave plate should have the retardation equal to ±90°, the polarizance close to zero, and the high throughput over 50%. The multilayer designs presented here achieve these conditions necessary for good and useful quarter-wave plates.

© 1992 Optical Society of America