FDTD simulation of 3D surface plasmon polariton band gap waveguide structures

Fundamental to progress in integrated optical systems are techniques for controlling light propagation on small spatial scales. The development of photonic band gap (PBG) waveguides (Joannopoulos, J.D. et al., 1982) represents a major step towards achieving such control, as it permits the nearly lossless redirection of light flows through sharp waveguide bends, a feat unachievable using conventional optical waveguide structures. Recently, a new kind of optical waveguide was introduced that exploits the existence of surface plasmon polaritons (SPP) on metals in the optical regime to construct surface-based PBG structures (Kitson, S.C. et al., Phys. Rev. Lett., vol.77, p.2670-3, 1996; Bozhevolnyi, S.I., Phys. Rev. Lett., vol.86, p.3008-10, 2001). These SPPBG waveguide structures introduce interesting mechanisms for controlling light flow beyond the possibilities offered by conventional PBG waveguides. Notable experimental progress in the construction and characterization of SPPBG waveguides notwithstanding few efforts, to date, have been directed at their theoretical/computational analysis. Here, we report on the implementation of a three-dimensional (3D) finite difference time domain (FDTD) scheme for simulating wave propagation in SPPBG waveguides. In addition, two specific SPPBG bent waveguide geometries are analyzed.