This talk will present our on-going effort to control the dipole-dipole interaction between cold Rydberg atoms. In our experiment, we trap individual atoms in two-dimensional arrays of optical tweezers separated by few micrometers and excite them to Rydberg states using lasers. The arrays are produced by a spatial light modulator, which shapes the dipole trap beam. We can create almost arbitrary geometries of the arrays.
We have measured the van der Waals interaction between two individual atoms, and show efficient Rydberg blockade in arrays of three atoms. We have also demonstrated the control of the interaction between atoms with microwave and DC electric fields. We observe in particular the coherent energy exchange between two atoms resulting from their dipole-dipole interaction. This control of the interaction will find applications in quantum state engineering, quantum information and quantum simulation.