Figure 4
One-photon event image against a two-photon event image. Images consisting of (a) one-photon events and (b) two-photon events of a binary star target acquired over 10,000 frames. The object is illuminated by the SPDC source at a light level where the number of photon illumination events is 4.70 times the dark noise events of the camera. Each image is normalised independently to allow representation on the same scale. Also shown is a cross-section of image intensity against pixel number (c), for the one-photon (blue) and two-photon (red) event images. Cross-section rows 80–110 of the images as indicated by the blue dotted lines on the image in Fig. 5. For each column in the selected rows the mean value was calculated for the one-event image and the two-event image. These mean values were normalised independently by dividing the maximum value for each respective cut as to allow representation on the same scale. All events registered as per our described analysis are present in the images and no background subtraction has been performed.
