  We present the first experimental realisation of the quantum illumination
protocol proposed in Ref.s [S. Lloyd, Science 321, 1463 (2008); S. Tan et al.,
Phys. Rev. Lett. 101, 253601 (2008)], achieved in a simple feasible
experimental scheme based on photon-number correlations. A main achievement of
our result is the demonstration of a strong robustness of the quantum protocol
to noise and losses, that challenges some widespread wisdom about quantum
technologies.
