[Paper Review] Ghost Imaging with Blackbody Radiation

Yangjian Cai, Shi‐Yao Zhu|ArXiv.org|Jul 29, 2004

Random lasers and scattering media1 references3 citations

TL;DR

This paper presents a theoretical framework for ghost imaging using blackbody radiation, deriving a Gaussian thin lens equation that depends on both optical paths. It shows that image quality improves with higher blackbody temperature and larger source size, but visibility decreases due to classical intensity fluctuations, contrasting with quantum ghost imaging where high visibility and quality coexist via entanglement-induced correlations.

ABSTRACT

We present a theoretical study of ghost imaging by using blackbody radiation source. A Gaussian thin lens equation for the ghost imaging, which depends on both paths, is derived. The dependences of the visibility and quality of the image on the transverse size and temperature of the blackbody are studied. The main differences between the ghost imaging by using the blackbody radiation and by using the entangled photon pairs are image-forming equation, and the visibility and quality of the image

Motivation & Objective

• To investigate whether ghost imaging can be achieved using classical blackbody radiation instead of entangled photon pairs.
• To derive a ghost imaging formation equation for blackbody radiation based on optical coherence theory.
• To analyze the dependence of image visibility and quality on the blackbody's temperature and transverse size.
• To compare classical ghost imaging with blackbody radiation to quantum ghost imaging using entangled photons.
• To clarify the role of intensity fluctuations (Hanbury Brown-Twiss effect) in classical ghost imaging, distinguishing it from quantum entanglement.

Proposed method

• Derives the fourth-order correlation function for blackbody radiation using second-order coherence theory.
• Applies Collin's formula and response functions for both optical paths to model the system.
• Uses a quasi-Gaussian approximation for the second-order correlation function, dependent on temperature and source size.
• Derives a Gaussian thin lens equation for image formation that depends on both paths.
• Introduces an image quality factor Q to quantify image sharpness, defined via the ratio of integrals of the transfer function.
• Compares classical ghost imaging with quantum ghost imaging by analyzing differences in the cross-correlation function and imaging equations.

Experimental results

Research questions

• RQ1 Can ghost imaging be achieved with classical blackbody radiation, and if so, under what conditions?
• RQ2 How do the temperature and transverse size of the blackbody affect image visibility and quality?
• RQ3 What is the form of the image formation equation in classical ghost imaging with blackbody radiation?
• RQ4 How does the classical ghost imaging mechanism differ from quantum ghost imaging using entangled photons?
• RQ5 What role does the Hanbury Brown-Twiss effect play in classical ghost imaging, and how does it limit visibility?

Key findings

• The image formation equation for blackbody radiation follows a Gaussian thin lens equation, but with a sign reversal in the path length term compared to the quantum case.
• Image quality (Q) increases with higher blackbody temperature and larger transverse size, approaching perfection as both tend to infinity.
• Visibility decreases as temperature and size increase, reaching zero in the infinite-temperature limit, due to background noise from intensity fluctuations.
• High image quality and high visibility cannot coexist in classical ghost imaging, unlike in quantum ghost imaging with entangled photons.
• The cross-correlation function in classical imaging contains |E*(x)|² instead of |E(x)|², leading to background noise that limits visibility.
• Replacing the lens in path two with a phase-conjugating mirror would alter the imaging equation, suggesting potential for image correction.