  Use of non-classical light in a quantum illumination scheme provides an
advantage over classical illumination when used for LIDAR with a simple and
realistic detection scheme based on Geiger-mode single photon detectors. Here
we provide an analysis that accounts for the additional information gained when
detectors do not fire that is typically neglected and show an improvement in
performance of quantum illumination. Moreover, we provide a theoretical
framework quantifying performance of both quantum and classical illumination
for simple target detection, showing parameters for which a quantum advantage
exists. Knowledge of the regimes that demonstrate a quantum advantage will
inform where possible practical quantum LIDAR utilising non-classical light
could be realised.
