Diode-laser-based High Resolution Spectroscopy in Sm I

Abstract

The present paper reports more extensive and precise experimental results about the isotope shifts of Sm I in the 635 nm — 690 nm range by Doppler-free saturation absorption spectroscopy using a single-mode diode laser with a small linewidth. We measured newly the isotope shifts and hyperfine structures of 20 transition lines, which are mostly originating from the [4f ⁶6s ²] ⁷ F _J to [4f ⁶6s6p] ⁹ D _o ⁹ F _o and ⁷ G _o levels, with a resolution better than 8 MHz. The measured isotope shifts were resolved into mass shifts and field shifts by King plot analysis. Finally, we could obtain the changes in mean-square nuclear charge radii from field shifts, and they were compared with the previous results.