Above-threshold two-colour ionization signal of singly charged neon

In this work we report the ionization of a gaseous neon target by combining extreme ultraviolet (XUV) radiation from the Free Electron Laser in Hamburg with an intense synchronized optical laser. The photoelectron spectrum dependence of the electrons ejected from singly-charged neon (Ne+) on the relative polarisation of the XUV and optical laser fields was investigated both experimentally and theoretically.