The conserved vector flux is a useful construct for analyzing and designing optical concentrators. We derive an expression for the flux, starting from the free radiation field. With our method, conservation of the flux is automatic, and limits to conservation in certain optical systems follow.
© 1986 Optical Society of America
R. Winston and X. Ning, "Constructing a conserved flux from plane waves," J. Opt. Soc. Am. A 3, 1629-1631 (1986)