Physical Review A
Microwave spectroscopy of the cold rubidium (n+1)d5/2→ng and nh transitions
Jeonghun Lee, Jirakan Nunkaew, Thomas F. Gallagher
Abstract
We present an experimental technique that allows us to determine the zero-field intervals between high-$\ensuremath{\ell}$ states of Rb in a magneto-optical trap, in spite of the fact that we can only control the stray electric field in one direction. The technique is based on measuring a property of the atom that depends on the field, as opposed to its square. This approach allows the determination of the zero-field intervals and the magnitude of the stray field in the uncontrolled perpendicular direction. We use this technique to observe the microwave transitions of rubidium from the $(n+1){d}_{5/2}$ states to the $ng$ and $nh$ states of $27\ensuremath{\le}n\ensuremath{\le}30$. From the observed microwave transitions, we determine the quantum defects of the $ng$ and $nh$ states. Using the quantum defects of the $ng$ and $nh$ states and the adiabatic core polarization theory, we determine the ${\mathrm{Rb}}^{+}$ ionic dipole and quadrupole polarizabilities to be ${\ensuremath{\alpha}}_{d}=9.12(2){a}_{0}^{3}$ and ${\ensuremath{\alpha}}_{q}=14(3){a}_{0}^{5}$, respectively.