Transverse magnetic mode slab waveguide optical sensor in the presence of conducting interfaces

In this paper, three layer slab waveguide is considered for the p-polarization whose free charge layer with a surface conductivity is assumed to exist at the two interfaces. The structure is then enhanced for sensing process by considering the different refractive index analytes in its proposed cladding structures. The sensitivity of the proposed sensor is investigated in details. Positive as well as negative surface conductivities are considered. It is found that utilizing negative surface conductivity at the interfaces can significantly enhance the sensitivity.