Spin-motion coupling using the transverse field gradient of a laser beam*

As we continue to push toward an ion-based gyroscope interferometer [1], we observe spin-motion coupling of an ion using a single laser beam that drives a stimulaed Raman transition. Transferring momentum to an ion during a laser-driven transition requires a spatial gradient in the Rabi frequency which is typically achieved through the interference of two non-copropagating laser beams. Here [2], we demonstrate momentum transfer perpendicular to the laser beam's wavevector using the spatial gradient of the transverse beam profile. This effect may already be playing an unappreciated role in trapped-ion qubit gates.

[1] W. C. Campbell and P. Hamilton, J. Phys. B. 50, 064002 (2017)

[2] Adam D West et al., Quantum Sci. Technol. 6 024003. (2021)