A1_2 Single Photon Vision

Abstract

This paper considers a hypothetical human eye capable of registering a single photon as a conscious image in the brain.  To such an eye,  a receding light source would not grow faint to the point of vanishing, but instead would eventually register in the brain as flickering of individual photons.  The psychophysical concept of flicker fusion frequency is used to determine the threshold distance at which the receding light source ceases to appear continuous.  Simple lasers with varying angular divergence are used to model the scenario.