HG modes are of particular importance because of their potential to excite narrow-line transitions with simultaneous suppression of the undesirable light shift.
This can be achieved since HG beams exhibit highly inhomogeneous intensity profiles with a low-intensity center. An atom or ion, placed in this center, is exposed to an electric field of low strength but high gradient, which favors non-dipole transitions but weakly perturbs atomic levels. However, such an excitation scheme may suffer from imprecise localization of a target ion relative to the low-intensity center due to the lack of laser beam pointing stability. We propose to solve this problem using integrated schemes in which the light delivery optics is fabricated directly into the atom traps. To assess the feasibility of this approach, we present a theoretical analysis of the excitation of the 2S1/2 → 2F7/2 electric octupole transition in a single trapped Yb+ ion. Calculations, performed for realistic experimental parameters, help to determine the optimal combinations of incident light polarization and magnetic field orientation necessary for the successful realization of the proposed spectroscopy scheme. The study was conducted jointly with the theory institute FPM from PTB Braunschweig.
You can find the full paper here.
News from our research group
Our article "Excitation of Forbidden Electronic Transitions in Atoms by Hermite–Gaussian Modes" has been featured on the cover of Annalen der Physik
