Broadband multilayer polarizers at the energy range of 50-1000eV

Studies of polarization-sensitive, such as circular dichroism spectroscopy, spin-polarized photoelectron spectroscopy and spectroscopic ellipsometry, accurate evaluation of the polarization state of the radiation is clearly crucial, which requires polarization optical elements, such as polarizer, analyzer and phase retarder. In EUV and soft x-ray region, the closeness of the real part of the refractive index to unity, coupled with high absorption, makes the realization of polarizers such like birefringence and dichroic polarizers impossible. Periodical multilayers are commonly used in polarization study working at the quasi-Brewster angle due to their interference structures. In order to expand the narrow spectral bandwidth of the periodic multilayer, the aperiodic multilayer and lateral gradual multilayer polarizers including reflective analyzers and transmission phase retarders are utilized. In this work, we demonstrate a series of periodic, aperiodic and lateral gradual broadband multilayer polarizers with the material combinations of Mo/Si, Mo/Y, Mo/B4C, Cr/C, Cr/Sc, Cr/Ti, Cr/V and W/B4C. Different types of multilayer polarizers correspond to different energy ranges, covering the energy range of 50- 1000eV, including “water window” and the L absorption edges of Fe, Co and Ni. Polarization measurements are performed at National Synchrotron Radiation Laboratory in Hefei and Beijing Synchrotron Radiation Facility. Some of the polarizers we have developed are applied to the polarization measurements of Beam-line 3W1B of Beijing Synchrotron Radiation Facility.