Surface Plasmon Modes of Dielectric-Metal-Dielectric Waveguides and Applications

Abstract

The dielectric-metal-dielectric plasmonic waveguide structures find applications in integrated optics and fiber polarizers and sensors. Surface plasmon waves guided by thin metal film have been intensively studied over the last two decades. However, most studies have been confined to relatively low index dielectrics. With growing interest in silicon photonics and other semiconductors dielectric of relatively higher dielectric constant we carried out a detailed study of the modes supported by a metal filmbetween dielectrics of relatively higher dielectric constant. The study clearly shows that both modes, the"antisymmetric" (í µí±Ž í µí±) short range and "symmetric" (í µí± í µí±) long range bound modes can exist only when the contrast between the indices is low. For high contrast the symmetric mode transforms into a leaky mode.For completeness we also includethe antisymmetric leaky (í µí±Ž í µí±™) mode and symmetric leaky (í µí± í µí±™) mode in our study, although they are not important for guided wave structures. We have also included "leaky modes" in the bound mode domain as solution of the boundary value problem as reported in some early studies. We have also considered some applications of the DMD waveguides with an emphasis on identifying the participating mode in each application.