Fig. 2.

TE-polarized Bloch surface waves excited with ED and MD sources. Simulation by FDTD of the coupling of a an ED source oriented along the x axis and b, c a spinning MD source, to a TE-polarized BSW. All three results show, in false colors, the absolute value of the real part of the electric field ($∣Re\left(E_x\right)∣$). The MD rotates either b anti-clockwise or c clockwise. d Directionality factor (ratio of the electric intensities for the left and right BSWs) for various MD polarizations. The MD polarization ellipticity is changed along the path shown in red in the Poincare sphere (see inset). The MD moment is also expressed at specific values of the ellipticity angle 2χ related to the Poincare sphere