Photon-photon interaction in cold gases

We realize the limit of quantum nonlinear optics, where photons interact strongly among themselves. Employing the dipolar interaction between Rydberg atoms inside a cold gas, we make photons scatter, attract, or repel each other.

Imagine nonlinear optics pushed to the extreme limit of the quantum world, at the sub-picowatt levels. In this regime, the particle-like nature of light becomes significant, and the individual photons appear to interact. The photons bunch in pairs when they attract each other, or anti-bunch when they scatter each other.

Read more about quantum nonlinear optics and its applications or check out the tale of Pinkey and the Brain.

We are constructing a system where a cloud of ultra-cold atoms will be used to realize effective interactions between few photons as they propagate through it. Using auxiliary laser light,  structured in space, we will tune the nature of the interaction between the photons and their  energy landscape. We hope to explore the non-equilibrium dynamics of the quantum few-body system under tailored, complex, and well-controlled conditions.