Laser spectroscopy of metastable palladium at 340 and 363 nm

We report measurements of the isotope shift of the mass 104, 105, 106, 108, and 110 stable palladium isotopes for transitions from the metastable state $4{d}^{9}{(}^{2}{D}_{5/2})5s,{\phantom{\rule{0.16em}{0ex}}}^{2}{[5/2]}_{3}\ensuremath{\rightarrow}4{d}^{9}{(}^{2}{D}_{5/2})5p,{\phantom{\rule{0.16em}{0ex}}}^{2}{[7/2]}_{4}^{o}$ at 340 nm, and $4{d}^{9}{(}^{2}{D}_{5/2})5s,{\phantom{\rule{0.16em}{0ex}}}^{2}{[5/2]}_{3}\ensuremath{\rightarrow}4{d}^{9}{(}^{2}{D}_{5/2})5p,{\phantom{\rule{0.16em}{0ex}}}^{2}{[3/2]}_{2}^{o}$ at 363 nm. For $^{105}\mathrm{Pd}$, we determine the hyperfine structure of both transitions. The measurements were performed by saturation absorption spectroscopy in a custom-built hollow cathode lamp and will serve as a reference for collinear laser spectroscopy of short-lived neutron-rich palladium isotopes. We also report on the observation of a population inversion for the 363-nm transition under certain discharge conditions.