Ghost imaging: Open secrets and puzzles for undergraduates

Abstract

Ghost imaging, a novel technique in which the object and the image system are on separate optical paths, was first demonstrated using entangled photon pairs. This demonstration caused it to be regarded as a purely quantum effect, but subsequent work gave wide support to a classical explanation. We provide an introduction to ghost imaging based more on intuition than on formalism and discuss several experiments that can be implemented in a university physics laboratory.