Performance evaluation of a soft x-ray quadruple reflection circular polarizer

Abstract

We built a quadruple reflection polarizer which can be used in the energy range hν=8–130 eV to convert linearly polarized synchrotron radiation into circularly polarized light of either left or right handedness. The design permits independent adjustment of the angle of reflection θ as well as the angle of rotation α along the light axis. These adjustments allow us to operate the polarizer at any given energy in a mode where either the degree of circular polarization Pcirc or the figure of merit TP2circ is maximized. We tested the optical performance and phase shifting properties of a prototype polarizer using a bending magnet beamline. The data verify our model calculations of the conversion efficiency and the optimum operating parameters to maintain the highest degree of circular polarization.