In this paper we report a new ellipsometry method for soft X-ray SHG to suppress the contribution of second-harmonic radiation from the light source. Through measurements of a GaAs(100) crystal, we demonstrate that pure SHG signals can be obtained for the horizontally polarized component. The present method is generally applicable regardless of the incident photon energy and hence the absorption edge of the targeted materials. If combined with optical filters blocking the second-harmonic radiation and equipped with soft X-ray phase shifters, the method allows one to obtain further information from SHG signals such as tensor components of second-order nonlinear susceptibility.

This method paper was published under the leadership of our collaborators from the University of Tokyo.

Our paper was now published in e-Journal of Surface Science and Nanotechnology:
https://www.jstage.jst.go.jp/article/ejssnt/20/1/20_2022-002/_arti