New Theory of Light Emission

Richard M. Sillitto

Mario Yokota

The interrelation between the theories of transition probability and susceptibility χ on nonlinear spectroscopy becomes clear through a new formula with which we can evaluate the emission rate of observed photon energy. Necessary assumptions, on which the emission rate of the fourth wave in a four-wave light mixing processes is proportional to |χ|2, are investigated.

Li You, Jan Mostowski, J. Cooper

This is the first of a series of papers on the theory of cone emission from a laser-pumped two-level atomic medium. Starting from microscopic quantum theory for both the active medium and the field, equations for the slowly varying macroscopic quantities are derived. In the steady-state limit, which experimentally corresponds to cw excitation, we find that the sources for the paraxial fields of interest have a long coherence length despite the random nature of spontaneous emission. These radiation sources enter into the equations for the fields in the same form as the source generated by four-wave mixing and therefore may be considered as a ``spontaneous four-wave mixing,'' since the photons emitted in the Rabi sidebands are correlated. This has far-reaching consequences on the physics of cone emission and also sheds some new light on the fluoresence from strongly driven atomic systems.

John Christian William McKinley

This paper states a narrow observational no-go: no photon has ever been seen in flight. Every observation of light is a registration at a detector, never an observation of a photon between emission and absorption. Within standard photodetection theory, detecting a photon means registering an interaction, typically absorption, at a detector. Any attempt to observe a photon at an intermediate point would itself constitute a new registration, terminating the prior relation rather than revealing an in-flight photon. The paper introduces no new equations, no new observables, and no modification to special relativity, general relativity, quantum mechanics, quantum field theory, Maxwell’s equations, or standard optics. Its claim is observational only: the familiar image of light crossing the sky as a visible thing in flight is not something physics has ever recorded. What is observed are registrations, scattering events, emissions, absorptions, and detector records. No photon has been seen in flight.