Guided surface waves over a free-space-chiral interface: applications to identification of optically active materials

At a free-space-chiral interface, the complete modal expansion of the electromagnetic fields consists of the radiation fields and lateral waves, associated with branch cut integrals as well as guided surface waves associated with the poles of the like-and cross-polarized elements of the reflection matrix. The cross-polarized surface waves, considered here in detail, are proportional to the chiral measure and contain the footprints of the optical activity of the material. Explicit expressions are desired for the residue contributions at the poles of the cross-polarized reflection coefficients in terms of the optical activity. Thus, measurements of the ratio of the cross-to like-polarized surface waves, which can be excited by electric or magnetic dipoles near the interface, can be used to identify the optically active materials. (C) 2011 Optical Society of America