Dispersive optical nonlinearities using cold Rydberg atoms

Thibault Peyronel, Ofer Firstenberg, Qiyu Liang +1 more

Thibault Peyronel, Ofer Firstenberg, Qiyu Liang +2 more

Valentina Parigi, Erwan Bimbard, Jovica Stanojevic +5 more

We observe and measure dispersive optical nonlinearities in an ensemble of cold Rydberg atoms placed inside an optical cavity. The experimental results are in agreement with a simple model where the optical nonlinearities are due to the progressive appearance of a Rydberg blockaded volume within the medium. The measurements allow a direct estimation of the "blockaded fraction" of atoms within the atomic ensemble.

Valentina Parigi, Erwan Bimbard, Jovica Stanojevic +5 more

The realization of nonlinear optical effects at the single photon level would be a significant step forward for quantum information processing and communications. In particular, a strong dispersive and non-dissipative nonlinearity could enable the implementation of a two-photon phase gate. One possible strategy to reach such huge nonlinearities is to convert photons into strongly interacting particles, like collective excitations involving Rydberg atoms. Interactions between Rydbergs in fact lead to a “blockade” phenomenon, where each Rydberg atom blocks the excitation of its neighbors, which can result in strong nonlinearities. Here, we use an ensemble of cold Rydberg atoms inside an optical cavity to create large dispersive nonlinearities on a weak probe beam far detuned from a D2-line transition in87Rb atoms [1]. The used three-level ladder scheme, with a second control field detuned from resonance on the upper transition towards a Rydberg level, is shown in Fig.1a). A simple explanation of the nonlinear effect is the following: if a very weak probe beam is injected into the cavity in the presence of the blue light on the two-photon transition, it experiences the single-atom three-level dispersion described by the real part of the three-level susceptibility χ-3level. This corresponds to a certain shift of the transmitted cavity peak (Fig. 1b)).

Charles S. Adams

Jin‐Hui Wu, M. Artoni, Giuseppe Carlo La Rocca

We study the interaction between a probe and a trigger weak fields in a sample of cold rubidium atoms in the presence of a coupling and a dressing strong fields. Dipole Rydberg blockade may occur and can be set to depend on the probe and trigger polarizations giving rise to diverse regimes of electromagnetically induced transparency (EIT) with a concomitant small probe and trigger absorption and dispersion. This is shown to be relevant to the implementation of polarization conditional probe and trigger cross nonlinearities in cold Rydberg atoms.