We report the laser cooling of a single ${{}^{40}\mathrm{Ca}}^{+}$ ion in a Penning trap to the motional ground state in one dimension. Cooling is performed in the strong binding limit on the 729-nm electric quadrupole $S_{1/2}\leftrightarrow D_{5/2}$ transition, broadened by a quench laser coupling the $D_{5/2}$ and $P_{3/2}$ levels. We find the final ground-state occupation to be 98(1)%. We measure the heating rate of the trap to be very low with $\dot{\overline{n}}\approx 0.3(2){\mathrm{s}}^{-1}$ for trap frequencies from 150–400 kHz, consistent with the large ion-electrode distance.

• Received 25 July 2014

DOI:https://doi.org/10.1103/PhysRevLett.116.143002

This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

Published by the American Physical Society