Two-photon ac-Stark effect in Raman-Ramsey Interactions

For the two-photon ac Stark effect in Raman-Ramsey configuration, such as the Raman clock, and pulsed CPT clock configuration, an interference phenomenon of two-photon ac Stark effect is predicted. Here we report this new physical phenomenon, the interference of two-photon ac Stark effect in two-zone Raman-Ramsey interactions, which is general in any Raman-Ramsey spectroscopy. In particular, for an atomic beam Raman clock configuration, the ac Stark shift will present an interference fringe caused by the separated oscillatory-field interaction when the shift fields interact with atoms at two zones. On the center of dispersion shape of normal ac-Stark shift, an interference pattern appeared when the scale of frequency detuning is expanded.