Multi-color resonance ionization of laser ablated gadolinium at highlaser power

Spectroscopic and analytical properties of a trace analytical method using multi-step resonance ionization at high laser intensities (>kW/cm2) have been investigated with gadolinium as a test element. Strongly saturated transitions are observed, which have been used for a temperature determination of the atoms in the laser ablated plume. Regimes of multi-step resonance ionization and multiphoton ionization could be distinguished. Analytical performances due to resonance enhancement and resulting discrimination against non-resonant background, precision in isotope ratio determination and overall detection efficiency are discussed