Absolute extreme ultraviolet yield from femtosecond-laser-excited Xe clusters - art. no. 036404

Large Xe clusters (10(5)-10(6) atoms per cluster) have been irradiated with ultrashort (50 fs) and high-intensity (similar to2 x 10(18) W/cm(2)) pulse s from a Ti:sapphire multi-TW laser at 800 nm wavelength. Scaling and absol ute yield measurements of extreme ultraviolet (EUV) emission in a wavelengt h range between 7 and 15 nm in combination with cluster target characteriza tion have been used for yield optimization. Maximum emission as a function of the backing pressure and a spatial emission anisotropy covering a factor of two at optimized yields is discussed with a simple model of the source geometry and EUV-radiation absorption. Circularly polarized laser light ins tead of linear polarization results in a factor of 2.5 higher emission in t he 11 to 15 nm wavelength range. This indicates the initial influence of op tical-field ionization for the interaction parameter range used and contras ts to collisional heating that seems to influence preferentially higher ion ization. Absolute emission efficiency at 13.4 nm of up to 0.5% in 2 pi sr a nd 2.2% bandwidth has been obtained.