Subwavelength Plasmonic Bragg Reflector Structures for On-chip Optoelectronic Applications

In this paper, we present a new plasmonic Bragg reflector with high reflectance efficiency in the optical frequency range. This structure is based on dielectric thickness modulation in the metal-insulator-metal (MIM) geometry which provides sub-wavelength light confinement and is suitable for high integration. We investigate and compare the performance of the presented structure with a previously proposed MIM-based reflector. We find that the reflector structures consisting of periodic change in their dielectric materials provide narrow band-gaps, and therefore are more appropriate for filtering applications. On the other hand, with the same effective index contrast, dielectric thickness modulation results in wider band-gaps and higher reflectance at frequencies inside the gap.