Ghost-imaging experiment by measuring reflected photons

A CCD array is placed facing a chaotic light source and gated by a photon counting detector that simply counts all randomly scattered and reflected photons from an object. A “ghost” image of the object is then observed in the gated CCD. Differing from all published ghost-imaging experiments, this setup captures ghosts from scattered and reflected light of an object, instead of the transmitted ones. This new feature is not only useful for practical applications, but is also important fundamentally. It further explores the nonclassical interference nature of thermal light ghost imaging.

Figure 1

(Color) ARL ghost image experiment schematic.

Figure 2

Ghost image of a toy figure.

Figure 3

(Color) Ghost image of “ARL” stencil. Upper: single frame CCD output. The “speckles” indicate typical random photodetection events. This experiment does not have a point-to-point imaging relationship between the source and the CCD. Each speckle of the CCD can be excited by any or by all speckles of the source. Middle: time averaged CCD output of a few hundred frames. Lower: CCD-$D_1$ joint detection.