Two-color spectroscopic studies of highly-excited atoms and laser-cooled ions

Hela Ladjimi, Wissem Zrafi, Mohamed Farjallah +2 more

We highlight the spectroscopic and electronic structure of BeCs + ion, theoretically investigating ground and low lying excited states as well as the cold ion–atom elastic collisions proprieties and laser cooling possibility.

Daniel Kleppner

Владимир Сергеевич Лебедев, И. Л. Бейгман

Wan, Yong

Laser spectroscopy is a versatile tool to investigate the internal structure of atoms, molecules and nuclei.High precision spectroscopy requires laser cooling to reduce Doppler broadening and Doppler shifts.Sympathetic cooling extends these advantages to species which do not have an appropriate transition for laser cooling and allows precision spectroscopy of previously inaccessible species using the quantum logic technique.The original implementation of quantum logic spectroscopy relies on the long lifetime of the excited spectroscopy state to realize a transfer sequence.Precision spectroscopy of transitions with a short-lived excited state is typically performed using laser induced uorescence or laser absorption spectroscopy.Neither of these methods has reached the fundamental quantum projection noise limit and are rather limited by photon shot noise.For these situations, we develop the technique of photon recoil spectroscopy as an extension of quantum logic spectroscopy to broad transitions.The common motion of a sideband-cooled two-ion crystal is excited by photon recoil during photon absorption on the spectroscopically investigated ion.This motional excitation is transferred to an internal state excitation on the co-trapped ion of a dierent species and detected with high eciency.We demonstrate the technique on the 2 S 1/2 ↔ 2 P 1/2 transition of the 40 Ca + ion and resolve the line center to 1/300 of its observed linewidth.The simplicity and versatility of the technique promises applications to other previously inaccessible species.A variation of the technique is proposed for rotational state preparation of molecular ions.A moving optical lattice is employed to exert a state-dependent force on the molecule.This would allow the detection of the rotational state of the molecular ion and therefore enable precision spectroscopy of specic rovibrational transitions in the molecule.

Masatomi Iizawa, Yasuhito Narita

Abstract Photoluminescent point defects, such as nitrogen vacancy (NV) color centers in diamond, have attracted much attention as solid-state qubits. In recent years, a method has been developed to dope ions one-by-one into a solid substrate with Ångström position accuracy using a Paul trap. However, the dopant atoms must be laser-cooled, and the atoms that are promising dopants for solid-state quantum devices, such as nitrogen, cannot be directly applied. In the previous studies, the cooling of the dopant ions has been achieved using a sympathetic cooling technique, in which the laser-cooled atoms are sandwiched, but this method has several problems such as the need for a mechanism to remove the laser-cooled atoms and the inability to distinguish between the dopant atoms and contaminations. We show that these problems can be overcome by directly cooling the hydrogenated ions instead of sympathetically cooling the ions, and the position accuracy can be improved.

Danijela Rostohar