Resonance ionization spectroscopy in a thermal lithium beam by means of diode lasers

Abstract

We measured two-step photoion current spectra by using a semiconductor laser and a Q-switched Nd:YAG laser with fourth-harmonic generation in an atomic lithium beam. The number of ions measured was compared with an estimate from the diode laser absorption measurement that uses a set of precisely solved rate equations. We explain the saturation effects on absorption by using transit time relaxation and detailed calculations of the ionization levels.