; Chen Kai
; Sun Li-Juan
; Xi Shi-Bo
; Yan Fen] Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China
; [Zhao Jia] Beijing Technol & Business Univ, Sch Mech Engn, Beijing 100037, Peoples R China
To develop polarizer functioning in the extreme ultraviolet (EUV) and soft X-ray region, the polarization performance of synthetic mica has been investigated theoretically with a simulation code using Fresnel equations and optical constants from the Henke database. The reflectance of synthetic mica crystal for s and p polarization was measured to investigate its polarization performance in a home-made synchrotron radiation soft X-ray polarimeter at beamline 3W1B, Beijing Synchrotron Radiation Facility (BSRF). The reflectivity of the synthetic mica crystal at an angle of grazing incidence of 48 degrees was obtained from the experimental data, which is about 4.8 x 10(-3) at 25 nm and 6.0 x 10(-4) at 12 nm, and the linear polarizance of the X-ray reflected by the synthetic mica crystal that we measured using an analyzer-rotating method increases from 80% to 96.6% in this EUV region, while higher than 98.2% in the simulation. The result indicates that this synthetic mica crystal works as a practical polarizer in this EUV region of 12-25 nm, and also in an extensive wavelength region higher than 25 nm.