A new two-photon ghost imaging experiment with distortion study

Differing from the early principle demonstrations, this practical ghost imaging experiment reports the first set of two-photon images captured by a photon counting CCD camera by means of jointly counting ‘reflected’ photons from the object. Interestingly, the CCD camera was not ‘looking’ at the object at all. Instead, the CCD camera was facing the chaotic light source. The output of the CCD camera was used for coincidence registration of the two-photon joint-detection events with another photon counting detector which simply collects all randomly reflected photons from the surface of the object. It is also interesting to find that the observed two-photon images are ‘distortion-free’, i.e. any disturbances made along the light path has no effect on the quality of the image. These experimental observations are not only useful for practical field-applications, but also important from a fundamental point of view. It rejects the ‘projection shadow’ idea in a non-deniable way and further explores the two-photon interference nature of thermal light ghost imaging.