Surface plasmon polariton mode in the metal-insulator-metal waveguide

Metal-insulator-metal (MIM) waveguides with subwavelength apertures exhibit unique properties that are considered breakthroughs in surface plasma technology. In this paper, we established a surface plasmon polariton (SPP) mode of MIM structure as well as a theoretical model of reflectivity and excitation coefficients to clarify the SPP mode structure. During simulation calculations, attenuation of the TM ground state mode with large-thickness dielectrics is over the oscillation mode, which is obviously different from the traditional dielectric waveguide. The TE mode exhibits characteristics of anamorphic dielectric optical waveguides, and its propagation distance is longer than that of the TM0 mode. With increasing length, the cavity quality factor Q increases, which indicates that the SPP reflection is limited. The quality factor of the cavity and the end-face have a close relationship. MIM waveguides with larger Q values can produce optical waves coupled with the SPP mode. In this paper, we analyzed SPP propagation constants and attenuation coefficients to promote the development of an integrated surface plasmon.