Null-field radiationless sources: comment

摘要

We elaborate on a recent paper by Hurwitz and Gbur [Opt. Lett. 39, 6529 (2014)], dealing with null-field sources. After commenting on their theory in Minkowski space, we show how the theory can be conveniently generalized to the case of curvilinear space. (C) 2015 Optical Society of America