Abstract
We have used quantum control to suppress the impact of random atom positions on coherent population transfer within atom pairs, enabling the observation of dipole-dipole driven Rabi oscillations in a Rydberg gas with hundreds of atoms. The method exploits the reduced coupling-strength sensitivity of the off-resonant Rabi frequency, and coherently amplifies the achievable population transfer in analogy to quasi-phase-matching in non-linear optics. Simulations reproduce the experimental results and demonstrate the potential benefits of the technique to other many-body quantum control applications.