MAXIMUM FAR-FIELD DIVERGENCE ANGLE OF A PLANE SOURCE

The far-field properties of a plane source with a constant phase distr ibution are presented. It is found, for the first time to our knowledg e, that for any plane source the theoretical upper limit of the far-fi eld divergence angle is shown to be 65.5 degrees. This result is diffe rent from what previous propagation and diffraction theories predicted , and when the size of the source approaches zero, the far-field behav ior of the plane source is also different from a spherical wave in hal f-space. (C) 1996 Optical Society of America