Spectral and ion emission features of laser-produced Sn and SnO_2 plasmas

We have made a detailed comparison of the atomic and ionic debris, as well as the emission features of Sn and SnO₂ plasmas under identical experimental conditions. Planar slabs of pure metal Sn and ceramic SnO₂ are irradiated with 1.06 μm, 8 ns Nd:YAG laser pulses. Fast photography employing an intensified charge coupled device (ICCD), optical emission spectroscopy (OES), and optical time of flight emission spectroscopy are used as diagnostic tools. Our results show that the Sn plasma provides a higher extreme ultraviolet (EUV) conversion efficiency (CE) than the SnO₂ plasma. However, the kinetic energies of Sn ions are relatively low compared with those of SnO₂. OES studies show that the Sn plasma parameters (electron temperature and density) are lower compared to those of the SnO₂ plasma. Furthermore, we also give the effects of the vacuum degree and the laser pulse energy on the plasma parameters.