Detection of single atoms and nuclei by methods of laser spectroscopy

Vladilen S Letokhov

Alexander V. Glushkov

Gloria B. Lubkin

A group at Oak Ridge National Laboratory reports that by means of the new technique of resonance ionization spectroscopy they have observed single atoms of cesium. They say that one atom in an environment of 1019 atoms or molecules of another kind can be measured with their method, and they do not believe this to be a limit. In subsequent experiments, the group has observed density fluctuations of atoms, absolute photodissociation cross sections, time-resolved diffusion and chemical reaction of atoms, and the detection of cesium atoms from the spontaneous fission of californium nuclei.

Munir Hasan Nayfeh

V. I. Balikin, G. I. Bekov, Vladilen S Letokhov +1 more

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.