CR SC MULTILAYERS FOR THE SOFT-X-RAY RANGE

We have systematically investigated ultrathin Cr/Sc multilayers (nanol ayers), using tunable soft-x-ray synchrotron radiation. The multilayer s were optimized for use either in normal incidence or at 45 degrees a t photon energies around the 2p-absorption edges of Sc (399 eV) and Cr (574 eV), respectively. They were sputter deposited on Si wafers or o n thin Si3N4-membrane support structures for use in reflection and in transmission, respectively, as polarizing and phase-retarding elements in a polarimeter. The performance theoretically expected with respect to reflection/transmission and energy resolution has been confirmed e xperimentally: A value of 7% for the normal-incidence peak reflectance at 395 eV was measured as well as a pronounced minimum in transmissio n for certain incidence angles and energies below the respective absor ption edges, indicating significant phase-shifting effects. (C) 1998 O ptical Society of America.