Observations on "nonradiating surface sources": comment

The proof, established in a recent paper [A. J. Devaney, "Nonradiating surface sources," J. Opt. Soc. Am. A 21, 2216 (2004)], of the existence of nonradiating surface sources formed by singlet-plus-doublet components whose generated fields vanish in either of the regions separated by a closed or infinite surface where the source resides is corroborated by means of an equivalent but slightly different formalism based on treatment of partial differential operators in a weak derivative or distributional sense. This approach yields a construction procedure applicable to a broad class of singular nonradiating sources. A fundamental question raised in that paper concerning the nonexistence of nontrivial nonradiating infinite planar sources that generate vanishing fields at both associated half-spaces is re-examined, with the conclusion that it is actually possible to mathematically construct such singular nonradiating sources as long as one allows for higher-order singularities such as certain combinations of singlet and triplet components.