Abstract

A sufficiency condition was recently derived for a planar secondary source to generate light whose normalized spectrum is the same throughout the far zone and across the source plane.¹ This condition is known as the scaling law because it implies certain invariance properties of the degree of spectral coherence of the source under scaling with wavelength. We derive a corresponding condition for light produced by 3-D primary quasihomogeneous sources. While the corresponding 3-D version of the scaling law is found to be a sufficiency condition for the normalized spectrum of the emitted light to be the same throughout the far zone, it has quite a different implication, which is discussed, regarding the relationship between the spectrum of the far field and the source spectrum.

© 1987 Optical Society of America