Precision spectroscopy with 40 Ca + ions in a Paul trap

Martina Knoop, J. Rink, M. Vedel +1 more

M Guggemos, M Guevara-Bertsch, D. Heinrich +4 more

We perform quantum logic spectroscopy with a 27 Al + / 40 Ca + mixed ion crystal in a linear Paul trap for a measurement of the intercombination transition in 27 Al + . Towards this end, Ramsey spectroscopy is used for probing the transition in 27 Al + and the clock transition in 40 Ca + in interleaved measurements. By using the precisely measured frequency of the clock transition in 40 Ca + as a frequency reference, we determine the frequency of the intercombination line to be = 1 122 842 857 334 736 (85) Hz and the Landé g -factor of the excited state to be = 0.428 133(2).

Hanns‐Christoph Nägerl, Christian F. Roos, H. J. Rohde +4 more

Anand Prakash, Akhil Ayyadevara, E. Krishnakumar +5 more

We present the design and fabrication of an endcap-type Paul trap. The trap is designed for studies with Ca+ and Yb+. The design, fabrication process, and characterization are presented in detail, with a focus on trapping a single compensated ion at the rf node. A custom-built imaging system of NA = 0.14 and magnification of ≈22× performs close to the diffraction limit and resolves multi-ion clusters. Controlled ion loading and characterization of the trap are performed using 40Ca+. The experimentally determined quadrupole coefficient of the trap is ≈0.3, which is very close to the design value. The relative frequency shift along the spectroscopy beam due to excess micromotion is at the level of 3.5 × 10−18 for 40Ca+. Applications of this trap encompass single-ion-based optical frequency standards, tests of fundamental physics, the study of mesoscopic Coulomb clusters, and the controlled interaction of a single ion with co-trapped atoms.

Martina Knoop, C. Champenois, Ph. W. Courteille +4 more

Martina Knoop