Enhancing the achievable sensitivity of coherent-state illumination by using photon-number-resolvable detection
De He, X. N. Feng, YangCao Wu, Hai‐Zhi Song, L. F. Wei · Physical Review A · 2024
Illumination is a binary signal-detection protocol to check whether the target exists in a noisy environment; its achievable sensitivity is practically related to the choice of illuminating sources and the methods for measuring echo-wave signals. Here we demonstrate that the achievable sensitivity of the usual coherent-state illumination (CSI) with homodyne detection in phase space can be significantly enhanced by alternatively employing the photon-number-resolvable (PNR) detection in Fock-state space for both single-shot and multiple-shot illumination scenarios. Furthermore, using a typical infrared-light CSI, we show how to optimize the thresholds of PNR detection to improve sensitivity gains for varying illuminating intensities. It is also demonstrated that the present CSI protocol possesses a comparative sensitivity advantage over the CSI using threshold detection without PNR capability. We also discuss feasible strategies to achieve these sensitivity gains in different noise environments and under varying illuminating intensities.