Sub-Doppler spectroscopy of 89Y

Abstract

Sub-Doppler resolution of atomic transitions is obtained by spatially resolved laser induced fluorescence in a diverging atomic beam created by laser ablation. Resonances are spatially separated by relativistic effects experienced between the probing radiation and the moving particles thus proving that it is a high-quality atomic beam. Fast neutral atomic beams of 89 Y having centroid energies up to 12 eV are interrogated with tuned, single-frequency laser light. Narrow, spatially separated points of light move along the probe axis and are imaged by detecting only the zero-velocity components of the fluorescence. Accordingly, the Y 2 D 3/2 →Y 2 D 3/2 0 transition centered near 16 146 cm Ϫ1 is resolved into its hyperfine components with line widths on the order of 55 MHz and with an equivalent resolution of Ϯ5 MHz ͑Ϯ0.0002 cm Ϫ1 ͒. The upper level hyperfine interaction constant derived from level splitting is ϩ89Ϯ5 MHz. An equivalent collimation ratio of 9 mrad is estimated for the expanding pulsed atomic beam. We propose that laser ablation of selected targets provides a unique source of neutral or ionic ground-state atoms and molecules for spectroscopic studies. Details of these experiments are discussed and analyzed.

Doppler-free ablation fluorescence spectroscopy of Ca for high-resolution remote isotopic analysis

“…To the best of our knowledge, Lynds et al are the only researchers who have published a study demonstrating sub-Doppler spectroscopy using laser ablation sources. 25 In their study, an ablation plume was produced in a vacuum, and the Doppler broadening of the fluorescence peak was narrowed by observing the fluorescence only from a limited geometrical area of the plume. However, it had a drawback of low sensitivity because the number of atoms contributing to the fluorescence signal was extremely small owing to the spatial limitation.…”