  In this article, we demonstrate theoretically and experimentally how one can
exploit correlations generated in monolithic semiconductor quantum light
sources to enhance the performance of optical target detection. A prototype
target detection protocol, the quantum time-correlation (QTC) detection
protocol, with spontaneous parametric down-converted photon-pair sources, is
discussed. The QTC protocol only requires time-resolved photon-counting
detection, which is phase-insensitive and therefore suitable for optical target
detection. As a comparison to the QTC detection protocol, we also consider a
classical phase-insensitive target detection protocol based on intensity
detection. We formulated the target detection problem as a probe light
transmission estimation problem, and we quantify the target detection
performance with the Fisher information criterion and the receiver operation
characteristic analysis. Unlike classical target detection and ranging
protocols, the probe photons in our QTC detection protocol are completely
indistinguishable from the background noise and therefore useful for covert
ranging applications. Finally, our technological platform is highly scalable
and tunable and thus amenable to large scale integration necessary for
practical applications.
