  We propose a novel protocol for quantum illumination: a quantum-enhanced
noise radar. A two-mode squeezed state, which exhibits continuous-variable
entanglement between so-called signal and idler beams, is used as input to the
radar system. Compared to existing proposals for quantum illumination, our
protocol does not require joint measurement of the signal and idler beams. This
greatly enhances the practicality of the system by, for instance, eliminating
the need for a quantum memory to store the idler. We perform a
proof-of-principle experiment in the microwave regime, directly comparing the
performance of a two-mode squeezed source to an ideal classical noise source
that saturates the classical bound for correlation. We find that, even in the
presence of significant added noise and loss, the quantum source outperforms
the classical source by as much as an order of magnitude.
