M. Verde1, F. Stopp1, M. Katz2, M. Drechsler2, C. T. Schmiegelow2, F. Schmidt Kaler1
1 Johannes Gutenberg-Universität Mainz
2 Universidad de Buenos Aires
We use twisted-light carrying orbital angular momentum to coherently drive the centerof-mass motion of a single ion lying in the vortex beam singularity. The 40Ca ion is confined in the 3D harmonic potential of a Paul trap and is addressed by a Laguerre-Gauss beam containing a total of two quanta of angular momentum, one from its polarization and one from its topological structure. Previously, have been shown that such beams can excite transitions with the two units of angular momentum being transferred to the motion of the valence electron with respect to the core [1,2]. Here, orbital angular momentum is used to coherently excite the ion’s center-of-mass motion in the plane perpendicular to the beam’s propagation direction, in sharp contrast to the case of standard Gaussian light. [3]. Moreover, by cooling the motional mode close to the ground state, red and blue sidebands show coherent oscillations governed by a new kind of Lamb-Dicke parameter which depends on the ratio between the ion’s wave packet size and the vortex light waist.
Fig. 1 Comparison between the single ion’s spectrum obtained with Gaussian (on the top) and twisted light (on the bottom). The center-of-mass motion perpendicular to the incident direction cannot be excited by Gaussian light, while it is coherently driven with the Vortex beam.
References
[1] Schmiegelow, C. T.; Schulz, J.; Kaufmann, H.; Ruster, T.; Poschinger, U. G. and Schmidt-Kaler, F.; Nature communications, 7, 12998 (2016)
[2] Schmiegelow, C.T. and Schmidt-Kaler, F.; The European Physical Journal D 66, 157 (2012)
[3] Stopp, F.; Verde, M.; Katz, M.; Drechsler, M.; Schmiegelow, C. T.; and SchmidtKaler, F.; arXiv:2206.04894 (2022) (Submitted to PRL)