Ghost “pinhole” imaging in Fraunhofer region

For an aperture with transverse size D, Fraunhofer region is named when the distance between the aperture and the detector is larger than D2/λ, where λ is the wavelength of the illuminating light. For a lensless system, when both reference detector and the object are located in Fraunhofer region relative to the thermal source, we demonstrate that a ghost “pinhole” camera with magnification M=z/z1 can be obtained by the second-order correlation of two light fields even if the test detector is a single pointlike detector. Effects determining the quality of ghost pinhole imaging and its potential applications are also discussed.