Stark shift of a single barium ion and potential application to zero-point confinement in a rf trap

Abstract

Recently we have observed the Stark shift in an optical transition of a single trapped ${\mathrm{Ba}}^{+}$ ion. To enhance the shift in the 6${\mathit{S}}_{1/2\mathrm{-}}$5${\mathit{D}}_{5/2}$ clock transition, the ion is displaced from the saddle point of the trapping potential. The Stark shift constants, ${\mathrm{\sigma }}_{\mathit{s}}$, for the three pairs of Zeeman components are found to be the following: 6.1(7), 7.5(8), and 11.7(12) mHz/(V/cm${)}^2$ for ‖${\mathit{M}}_{\mathit{S}}$‖=1/2 to ‖${\mathit{M}}_{\mathit{D}}$‖=1/2, 3/2, and 5/2 transitions, respectively. A scheme is also proposed to use the Stark shift to identify the zero-point confinement state of a single trapped ${\mathrm{Ba}}^{+}$ ion.