  Quantum target detection (QTD) utilizes nonclassical resources to enable
radar-like detection for identifying reflecting objects in challenging
environments, surpassing classical methods. To fully leverage the quantum
advantage in QTD, determining the optimal probe states (OPSs) across various
detection parameters and gaining a deeper understanding of their
characteristics are crucial. In this study, we identified the single-mode
continuous-variable OPSs for arbitrary object reflectivity using optimization
algorithms. Our findings suggest that OPSs are non-Gaussian states in most
reflectivity scenarios, with exceptions under specific conditions. Furthermore,
we provide a comprehensive physical interpretation of the observed phenomena.
This study offers a tool for identifying OPSs along with a clear physical
interpretation. It also contributes to further advancements towards optimal
multi-mode QTD, which has the potential for broad applications in quantum
sensing and metrology.
