Evanescent and propagating electromagnetic fields in scattering from point-dipole structures: comment.
I comment on the recent paper by Setälä et al. [J. Opt. Soc. Am. A 18, 678 (2001)]. In that paper the calculation is entirely and exactly adopted from our previous work except the evanescent-field propagator. I shall demonstrate that the replacement of the propagator flaws the calculation. In their paper the numerical results show rich subwavelength information at absolute far-field distances (four times larger than the wavelength). I shall point out that the evanescent resolution at far-field distances cannot be of subwavelength. In the paper by Setälä et al. the description of previous work is inaccurate and misleading. I shall give what I consider to be the correct guidelines for readers to learn about the standing controversy regarding the evanescent field of a dipole.
Xiao
Mufei
M
Centro de Ciencias de la Materia Condensada, Universidad Nacional Autónoma de México, Baja California. mufei@ccmc.unam.mx