Quantum illumination in the presence of photon loss

Quantum illumination can be used to detect the low-reflectivity target hidden in strong background noise. All known results are based on the assumption of ideal photon transmission and reception. In this paper, we investigate the impact of photon loss on the performance of quantum illumination in two distinct scenarios: (I) the probabilistic loss mode and (II) the hybrid loss model. In both scenarios it is shown that quantum illumination with bipartite entanglement outperforms its classic correspondence with coherent states in both error probability and its response to probabilistic photon loss. Moreover, in scenario I, the resource required in quantum illumination scales far less than 1/pch2 to completely compensate the channel efficiency pch2. This poses a sharp contrast with the consumption of classic illumination which scales as 1/pch2. However in scenario II, both quantum illumination and classic illumination need resources of more than 1/pch2, due to extra thermal noise introduced in the hybrid loss model.