Bloch surface wave excitation based on coupling from photonic crystal waveguide

In this paper, a way to excite a Bloch surface wave by coupling from the photonic crystal waveguide is presented. The Bloch surface mode in a two-dimensional photonic crystal appears in the bandgap by changing the size of surface rods. The dispersion relation of surface modes will be affected when altering the radius of surface rods. The co-directional and contra-directional couplings between these modes are also discussed. The coupled mode theory is used to study the coupling between the waveguide mode and surface mode of photonic crystals. Finally, finite element simulations are also presented.