Abstract

We have discovered from Michelson and Young interferometry experiments, carried out with the use of an argon laser (working at λ = 5145 Å, with intracavity etalon, cw, 1-W power) that the standard application of quantum electrodynamics (QED) to this problem is incorrect. Photons belonging to a chaotic mixture of |n〉 states behave as Bose-Einstein (BE) particles showing a large reduction of the interference-fringe visibility $V(\overline{n})=\left(I_{\max }-I_{\min }\right)/\left(I_{\max }+I_{\min }\right)$ for increasing average photon number per radiation mode $〈n〉=\overline{n}$, where $I(\overline{n})$ is the photodetected intensity. This effect, never investigated or anticipated before, is a manifestation of the quantum interparticle correlations inherent BE statistics. Photons belonging to a superimposition of coherent, Glauber, |α〉 states (i.e., a laser beam) follow Maxwell-Boltzmann (MB) statistics leading to $V(\overline{n})=1$ for any $\overline{n}$, owing to absence of interparticie correlations.

© 1986 Optical Society of America