Triangular lattice plasmonic photonic band gaps in subwavelength metal-insulator-metal waveguide structures

We present a slablike photonic crystal with two-dimensional lattice structure, which exhibits subwavelength light confinement in the transverse direction perpendicular to the lattice plane based on the metal-insulator-metal (MIM) configuration. Using a modified implementation of the plane wave expansion method, we calculate the band structure created by a periodic modulation in the dielectric region of a MIM waveguide. The resulting band structure is verified by finite-difference time-domain simulations. We show that the MIM photonic crystal can provide a wider band gap compared to that of the two-dimensional photonic crystals. © 2008 American Institute of Physics.