Design of low loss surface plasmon polariton waveguide and its use as hybrid Tamm sensor with improved sensitivity

A compact, dielectric–metal–dielectric surface plasmon polariton (SPP) waveguide is designed that can have propagation lengths as high as several thousand microns. The dielectric layers surrounding the metal waveguide are actually periodic layers of different nanometer-sized dielectric pairs. By proper selection of the surrounding layer widths, a device with a controllable effective index and increased compactness can be designed. It can have a propagation loss <1 dB / cm, which is much less than any conventional SPP waveguide. Introduction of a metallic layer outside the dielectric layer of this structure results in a hybrid Tamm plasmon polariton (TPP), which can be used for sensing applications. Its sensitivity and the figure of merit are reported at different operating wavelengths. It is seen that the proposed hybrid TPP structure can be used to detect a larger refractive index range with comparable or better sensitivity than other plasmonic sensors. Determination of different optical parameters required for the design is done using a semianalytical approach. All the necessary steps of the present analysis are discussed and the calculated results are matched and compared with similar results of the other researchers whenever required.