Sequential ionization inHe3with a 1.5-ps 1-μm laser pulse

Abstract

We have examined the laser ionization of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ using 1.053-μm 1.5-ps laser pulses. The use of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ rather than ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ in the experiment enables the detection of the second charge state separately from a troublesome background contaminant ${\mathrm{H}}_2^{+}$. In these experiments, the production of doubly charged ions is dominated by the sequential process rather than by the direct or simultaneous process.