Fig. 1. Schematic illustration of quantum temporal ghost imaging based on frequency correlation

Fig. 2. The experimental results of quantum temporal ghost imaging^[32]. (a) A typical coincidence count histogram; (b) two-dimensional imaging by step-moving the object

Fig. 3. Thermal temporal ghost imaging^[33]. (a) The schematic illustration of thermal temporal ghost imaging; (b) the coincidence count peak changes versus the filter’s bandwidth; (c) the coincidence count peak moves versus the filter’s center-wavelength

Fig. 4. The illustration of quantum secure ghost imaging^[40]

Fig. 5. Quantum secure ghost imaging^[40]. (a) The signal-to-ratio (SNR) of Bob’s image versus the photon records sent by Alice, the inset corresponds to the SNR threshold of the recognizable image; (b) Bob’s image when the visibility of the interference fringe decreases by 2%; (c) Eve’s image when the visibility of the interference fringe decreases by 2%