Ion and extreme ultraviolet emission features of CO2 laser produced Sn and SnO2 plasmas

Abstract

The plasma plume expansion, ion debris and extreme ultraviolet (EUV) emission features of CO2 laser-produced Sn and SnO2 plasmas are investigated in this work. The expansion parameters of laser-produced plasma (LPP) are estimated using a fast-gated intensified charge-coupled device (ICCD) imaging system, while the ion debris is detected using a Faraday cup and the time-of-flight (TOF) method. Additionally, the EUV emissions from CO2 laser-produced Sn and SnO2 plasmas are measured using a grazing incidence flat-field spectrograph and EUV photodiodes. The ICCD images show that the SnO2 plasma plume has a broader edge when compared with that of the Sn plasma. Because of the differences between the thermodynamic parameters of the samples, the total ion number and the kinetic energy were both higher for the SnO2 plasma than for the Sn plasma. The maximum estimated conversion efficiencies (CEs) of the Sn and SnO2 plasmas were 1.1% and 0.9%, respectively; the difference is due to the lower Sn fraction in SnO2. The results of the angularly-resolved EUV emission measurements showed that the detected EUV energy decreases as the angle with respect to the laser axis increases.