The Physics of Turbulence-Free Ghost Imaging

Since its first experimental demonstration, ghost imaging has attracted a great deal of attention due to interests in its fundamental nature and its potential applications. In terms of applications, the most interesting and useful feature, perhaps, is the turbulence insensitivity of thermal light ghost imaging, i.e., atmospheric turbulence would not have any influence on the ghost images of sunlight. Inspired by ghost imaging, a new type of camera is ready for turbulence-free imaging applications. This turbulence-free camera would be especially useful for long distance imaging, such as satellite imaging. How could fluctuations of thermal light produce an image? Why is it turbulence-free? This article addresses these questions.