Excitation of an Electric Octupole Transition by Twisted Light

We study the coherent excitation of the 2S1=2 -> 2F7=2 electric octupole (E3) transition by twisted light modes with a single 171Yb+ ion in the dark center of a vortex beam. The intensity distribution of the beam is mapped as a function of the ion's position by measuring the light shift on an auxiliary electric quadrupole transition. In the center of the vortex beam, we observe excitation of the E3 transition with a fivefold reduced light shift in comparison to excitation by plane wave radiation for the same Rabi frequency. We measure the excitation probabilities for Laguerre-Gaussian twisted light modes of first and second order for different polarization patterns at various orientations of the ion quantization axis with respect to the beam propagation vector. We compare the experimental results with theoretical predictions and find good qualitative agreement.

Automated summary

In this study, we investigate the coherent excitation of the 2S1=2 -> 2F7=2 electric octupole (E3) transition by twisted light modes with a single 171Yb+ ion in a dark center of a vortex beam. We measure the intensity distribution of the beam as a function of the ion's position and observe a fivefold reduced light shift in the excitation of the E3 transition compared to plane wave radiation. Furthermore, we compare the experimental results with theoretical predictions and obtain good qualitative agreement.