Laser Cooling of Radium Ions

Abstract

The unstable radium nucleus is appealing for probing new physics due to its high mass, octupole deformation and energy level structure. Ion traps, with long hold times and low particle numbers, are excellent for work with radioactive species, such as radium and radium-based molecular ions, where low activity, and hence low total numbers, is desirable. We address the challenges associated with the lack of stable isotopes in a tabletop experiment with a low-activity ($\sim 10\mu \mathrm{Ci}$) source where we laser-cool trapped radium ions. With a laser-cooled radium ion we measured the $7p{}^2{P}_{1/2}^o$ state's branching fractions to the ground state, $7s{}^2{S}_{1/2}$, and a metastable excited state, $6d{}^2{D}_{3/2}$, to be $p=0.9104(7)$ and $0.0896(7)$, respectively. With a nearby tellurium reference line we measured the $7s{}^2{S}_{1/2}\to 7p{}^2{P}_{1/2}^o$ transition frequency, 640.09663(6) THz.

5 pages, 4 figures

References in corpus (7)

• Precision Measurement of Time-Reversal Symmetry Violation with Laser-Cooled Polyatomic Molecules
• Experimental Realization of a Quantum Integer-Spin Chain with Controllable Interactions
• Dispelling the curse of the neutron skin in atomic parity violation
• Investigations of Ra${}^{+}$ properties to test possibilities of new optical frequency standards
• Spectroscopy of a synthetic trapped ion qubit
• Production and trapping of radioactive atoms at the TRI\muP facility
• Atomic parity violation and the standard model

Cited by in corpus (16)

• Opportunities for Fundamental Physics Research with Radioactive Molecules
• Probing Fundamental Symmetries of Deformed Nuclei in Symmetric Top Molecules
• Beyond the charge radius: the information content of the fourth radial moment
• Radium Ion Optical Clock
• The hyperfine anomaly in heavy atoms and its role in precision atomic searches for new physics
• Electric dipole transition amplitudes for atoms and ions with one valence electron
• Measurements and analysis of response function of cold atoms in optical molasses
• Measurements of electric quadrupole transition frequencies in ${}^{226}$Ra${}^{+}$
• Dipole-phonon quantum logic with alkaline-earth monoxide and monosulfide cations
• Laser cooling and trapping of ${}^{224}$Ra${}^{+}$
• Direct measurement of the $7s{}^2{S}_{1/2}\to$ $7p{}^2{P}_{3/2}$ transition frequency in ${}^{226}$Ra${}^{+}$
• Molecular laser cooling using serrodynes: Implementation, characterization and prospects
• Theoretical characterisation of the barium II and radium II ions
• Spectroscopy of electric dipole and quadrupole transitions in ${}^{224}$Ra${}^{+}$
• Lifetimes of the Metastable $6\mathrm{d}{}^2{\mathrm{D}}_{5/2}$ and $6\mathrm{d}{}^2{\mathrm{D}}_{3/2}$ States of Ra${}^{+}$
• Laser Cooling and Hyperfine Measurements of Radium-225 Ions