Excitation of Forbidden Electronic Transitions in Atoms by Hermite-Gaussian Modes

Photoexcitation of trapped ions by Hermite-Gaussian (HG) modes from guided beam structures is proposed and investigated theoretically. In particular, simple analytical expressions for the matrix elements of induced atomic transitions are derived that depend both on the parameters of HG beams and on the geometry of an experiment. By using these general expressions, the 2S1/2 & RARR;2F7/2$<^>{2}S_{1/2} \rightarrow \; <^>{2}F_{7/2}$ electric octupole (E3) transition is investigated in an Yb+ ion, localized in the low-intensity center of the HG(10) and HG(01) beams. It is shown how the corresponding Rabi frequency can be enhanced by properly choosing the polarization of incident light and the orientation of an external magnetic field, which defines the quantization axis of a target ion. The calculations, performed for experimentally feasible beam parameters, indicate that the achieved Rabi frequencies can be comparable or even higher than those observed for the conventional Laguerre-Gaussian (LG) modes. Since HG-like modes can be relatively straightforwardly generated with high purity and stability from integrated photonics, these results suggest that they may form a novel tool for investigating highly-forbidden atomic transitions.

Automated summary

In this study, the photoexcitation of trapped ions by Hermite-Gaussian (HG) modes from guided beam structures is proposed and theoretically investigated. Simple analytical expressions for the matrix elements of induced atomic transitions are derived, which depend on both the parameters of HG beams and the geometry of the experiment. The study focuses on the investigation of the 2S1/2 & RARR;2F7/2 electric octupole (E3) transition in an Yb+ ion localized in the low-intensity center of the HG(10) and HG(01) beams. The results suggest that HG-like modes could serve as a novel tool for investigating highly-forbidden atomic transitions, as they can be generated with high purity and stability from integrated photonics.