Abstract

It is shown that within the framework of exact statistical wave theory there is no realizable source that generates a field whose normalized spectrum is invariant on propagation, i.e. that is the same at every point outside the source domain. This result is established for three-dimensional primary sources and also for two-dimensional secondary sources. Nevertheless, as we will also demonstrate, there are sources that generate spatially invariant fields to a good approximation.

© 1992 Optical Society of America