Abstract

It is shown that for fields produced by quasi-homogeneous sources, one of the generalized radiance functions introduced by Walther¹ reduces, in the asymptotic limit of large wave number, to a function that has all the basic properties of the radiance of traditional radiometry. An explicit expression for this radiance is obtained in terms of the intensity distribution across the source and the degree of spectral coherence of the source. The results provide a rigorous foundation for radiometry in free space on the basis of statistical wave theory.

© 1985 Optical Society of America