Frequency shifts due to Stark effects on a rubidium two-photon transition

The 5S1/2→5D5/2 two-photon transition in Rb is of interest for the development of a compact optical atomic clock. Here we present a rigorous calculation of the 778.1-nm ac Stark shift [2.30(4)×10^-13(mW/mm²)^-1] that is in good agreement with our measured value of 2.5(2)×10^-13(mW/mm²)^-1. We include a calculation of the temperature-dependent blackbody radiation (BBR) shift, and we predict that the clock could be operated either with zero net BBR shift $[T=495.9(27)$ K] or with zero first-order sensitivity $[T=368.1(14)$ K]. Also described is the calculation of the dc Stark shift of 5.5(1)×10^-15/(V/cm²) as well as clock sensitivities to optical alignment variations in both a cat's eye and a flat mirror retroreflector. Finally, we characterize these Stark effects, discussing mitigation techniques necessary to reduce final clock instabilities.