AC Stark shift
= AC Stark shift
{c}
{title2=$\Delta E_g\simeq\hbar|\Omega|^2/(4\Delta)$}
= Light shift
{synonym}
The <energy> shift produced by an oscillating <electric field>, often called a <light shift>. For a far-detuned two-level drive with coupling $\hbar\Omega/2$ and $\Delta=\omega_L-\omega_{eg}$, the ground-state shift is approximately $\hbar|\Omega|^2/(4\Delta)$. Multilevel atoms can have polarization-dependent differential shifts.