Development of two-color resonant ionization sputtered neutral mass spectrometry and microarea imaging for Sr

Two-color resonant laser ionization sputtered neutral mass spectrometry offers high elemental selectivity. In this study, two-color resonance ionization in sputtered neutral Sr was confirmed by combining a grating type Ti:sapphire laser system and a time-of-flight secondary ion mass spectrometry (TOF-SIMS) system. The authors compared the ionization efficiencies of Sr of the two-color three-photon ionization scheme 1 (first step: 460.862 nm; second step: 767.519 nm) and the two-color two-photon ionization scheme 2 (first step: 460.862 nm; second step: 405.200 nm). The resonant ionization efficiency of the latter was found to be 50 times larger than that of the former. Finally, the authors mapped the microarea distribution of Sr by two-color resonant ionization sputtered neutral mass spectrometry.