Abstract

The optical spectra of neutral atoms are studied in superfluid helium (HeII). Neutral atoms are dispersed into HeII by laser ablation of solid samples immersed in HeII. Absorption and emission spectra of dispersed atoms are studied with pulsed dye lasers. Ytterbium is found to be a typical bubble atom which resides in a bubble-like cavity formed by a strong repulsive force against the surrounding He atoms. Resonance quenching of LIF by accidental overlap of the resonant induced emission and broad absorption lines is observed.