Contrast inverted ghost imaging with non-interacting photons

TL;DR

This paper demonstrates a novel form of ghost imaging using entanglement swapping with independent photons, producing contrast-reversed images and highlighting the role of state projection in quantum imaging.

Contribution

It introduces a new ghost imaging method based on entanglement swapping with non-interacting photons, resulting in contrast-reversed images, advancing quantum imaging techniques.

Findings

Ghost imaging achieved with non-interacting photons

Contrast reversal of images due to anti-symmetric projection

Potential for teleporting images across quantum networks

Abstract

Ghost imaging is the remarkable process where an image can be formed from photons that have not "seen" the object. Traditionally this phenomenon has required initially correlated but spatially separated photons, e.g., one to interact with the object and the other to form the image, and has been observed in many physical situations, spanning both the quantum and classical regimes. To date, all instances of ghost imaging record an image with the same contrast as the object, i.e., where the object is bright, the image is also bright, and vice versa. Here we observe ghost imaging in a new system - a system based on photons that have never interacted. We utilise entanglement swapping between independent pairs of spatially entangled photons to establish position correlations between two initially independent photons. As a consequence of an anti-symmetric projection in the entanglement swapping process, the recorded image is the contrast reversed version of the object, i.e., where the object is bright, the image is dark, and vice versa. The results highlight the importance of state projection in this ghost imaging process and provides a pathway to teleporting images across a quantum network.