Bertet P, Osnaghi S, Milman P, Auffeves A, Maioli P, Brune M, Raimond J M, Haroche S
Laboratoire Kastler Brossel, Département de Physique de l'Ecole Normale Supérieure, 24 rue Lhomond, F-75231 Paris Cedex 05, France.
Phys Rev Lett. 2002 Apr 8;88(14):143601. doi: 10.1103/PhysRevLett.88.143601. Epub 2002 Mar 25.
A two-photon Fock state is prepared in a cavity sustaining a "source mode" and a "target mode," with a single circular Rydberg atom. In a third-order Raman process, the atom emits a photon in the target while scattering one photon from the source into the target. The final two-photon state is probed by measuring by Ramsey interferometry the cavity light shifts induced by the target field on the same atom. Extensions to other multiphoton processes and to a new type of micromaser are briefly discussed.