Our XUV Phase Retarder acts as a quarter waveplate to turn linear polarized XUV light into circular 

polarized light without introducing noticeable dispersion. The phase retarder achieves close-to-

circular polarization of Pc=0.75 and obtains > 25% transmission around 66eV photon energy, where 

the Ni M2/M3 edge locates [1]. A broad spectral range from 40 to 85eV is supported to cover the M2/

M3 edge of 3 transition metals - Fe, Co and Ni. The retarder uses a transmission optimized, four mirror

grazing incidence reflection geometry that induces a quarter wave phase offset between -s and -p 

polarization component of a linear polarized input XUV beam. At the Ni M2/M3 transition up to 3% 

dichroism contrast is observed (i.e. > 85% of the theoretical value) [1]. A clear aperture of 3 mm will allow 

the low divergent XUV to pass through without clipping. Our XUV Phase Retarder is ideally geared to be 

combined with ultrafast high-harmonic XUV sources adding spin-sensitivity to conventional laser based 

pump-probe experiments via attosecond magnetic circular dichroism detection.