Axelrod, D. 2013. Evanescent Excitation and Emission in Fluorescence Microscopy. Biophys J. 104:1401–1409.
Eq. 3 includes an intermediate step d=1/2k3z, which is incorrect. It should read d=1/2|k1z|. The more consequential right side of Eq. 3 is still correct as it appears.