Slab waveguide sensor utilizing left-handed material core and substrate layers

Propagation of transverse electric (TE) polarized light in two three-layer slab waveguide structures comprising left-handed materials (LHMs) is studied for sensing applications. The LHM layer occupies the core layer in the first structure and the substrate layer in the second structure. The sensitivity of the effective refractive index of the guided mode to any change in the index of an analyte medium located in the cladding region is derived and studied. The optimal structure parameters corresponding to the highest sensitivity are found. The results reveal that the sensitivity of the second structure with LHM substrate is much higher than that of the first with LHM core layer. The sensitivity can reach up to 70% for the LHM substrate structure for some waveguide configurations whereas it can reach up to 45.5% for the LHM core structure. The sensitivities of the two structures are found to be significantly high when compared to those of the conventional three-layer slab waveguide structure comprising dielectric media.