Two-color optical nonlinearity in an ultracold Rydberg atom gas mixture

We report the experimental observation of strong two-color optical nonlinearity in an ultracold gas of Rb-85 - Rb-87 atom mixture. By simultaneously coupling two probe transitions of Rb-85 and Rb-87 atoms to Rydberg states in electromagnetically induced transparency (EIT) configurations, we observe significant suppression of the transparency resonance for one probe field when the second probe field is detuned at similar to 1 GHz and hitting the EIT resonance of the other isotope. Such a cross-absorption modulation to the beam propagation dynamics can be described by two coupled nonlinear wave equations we develop. We further demonstrate that the two-color optical nonlinearity can be tuned by varying the density ratio of different atomic isotopes, which highlights its potential for exploring strongly interacting multicomponent fluids of light.

Automated summary

The experimental observation of strong two-color optical nonlinearity in an ultracold gas of Rb-85 - Rb-87 atom mixture is reported. The nonlinearity can be tuned by varying the density ratio of different atomic isotopes, demonstrating potential for exploring strongly interacting multicomponent fluids of light. The phenomenon is described by two coupled nonlinear wave equations developed to explain the cross-absorption modulation to the beam propagation dynamics.