Nonclassical Excitation for Atoms in a Squeezed Vacuum

This is the authors' abstract. We don't add key points for this paper.

The two-photon transition 6S1/2→6D5/2 is investigated for trapped atomic cesium excited by squeezed light. The rate R of two-photon excitation versus intensity I is observed to be consistent with the functional form R0ex0ex=0ex0exβ₁I+β₂I², extending into a region with slope 1.3. This departure from the quadratic form for classical light sources is due to the fundamental alteration of atomic radiative processes by the nonclassical field.