Quantum-induced coherence imaging with a long interference region

Zou-Wang-Mandel (ZWM) quantum-induced coherence has been demonstrated for high-sensitive detection and sensing applications such as high signal-to-noise ratio ranging and imaging in complex environments. The path overlapping of the idler prohibits the determination of the exact path from which the signal originates. However, the interference region of quantum-induced coherence is limited to coherence length of parametric down-conversion (PDC) photons generated by nonlinear processes, which has remained an urgent issue to address. Here, we propose a method to increase the interference region of quantum-induced coherence imaging systems, from micrometers to centimeters at least by seed injection (SI) of the same frequency as the idler, and resulting in brighter fringes. Compared to typical ZWM quantum-induced coherence imaging, our system not only retains the advantages of noise resistance and no coincidence requirement but also exhibits possibilities of high-coherence, long-distance, and high-visibility imaging.