Comment on Ghost imaging with a single detector [arXiv0812.2633v2]

TL;DR

This paper clarifies the differences between pseudothermal and computational ghost imaging, emphasizing the role of source types and photon interactions, and corrects a misinterpretation of experimental results.

Contribution

It distinguishes PGI from CGI, clarifies the physics involved, and corrects the classification of a specific experiment as a simulation rather than an actual PGI.

Findings

CGI relies on two identical photons, one real and one simulated.

The experiment in question is a simulation, not a PGI experiment.

Differences in source types significantly affect ghost imaging physics.

Abstract

Computational ghost imaging has been demonstrated experimentally recently. In this comment we wish to clarify the difference between pseudothermal ghost imaging (PGI) and computational ghost imaging (CGI). In particular, to emphasize the physics that arises from the difference in the type of sources used. The experiment in [2] is not a PGI experiment but is a simulation of PGI. If we consider CGI at the single photon level, it becomes clear that CGI relies on two identical photons, one real and one simulated, to obtain an image.