Coherence of radiation from incoherent sources: II. Ball and disk sources and coherence of sunlight.

Abstract

Following the development of the companion paper [J. Opt. Soc. Am.36, 1433 (2019)JOAOD60740-323210.1364/JOSAA.36.00XXXX], additional models for the coherence of quasi-monochromatic light are constructed by placing incoherent monopole and dipole sources inside a spherical ball and on a circular plane disk. The paraxial approximation, which is valid for sunlight, reduces the number of different models from eight to three. Based on the solar images corresponding to these three models, the ball model is considered the most appropriate. The ball model can be modified to match the limb-darkening observations.