Propagation characteristics of silver nanorods based compact waveguides for plasmonic circuitry

We propose ultra-compact waveguides for plasmonic circuitry based on silver nanorods array embedded vertically into silicon on insulator (SOI) substrate for nanoscale guidance of optical frequencies. Silver nanorods array palisade silicon to form core of SOI waveguide and is theoretically modeled for the first time. Propagation characteristics of the structure are obtained using finite difference time domain (FDTD) computations, exposing bandgap in the visible regime for transverse magnetic modes and are verified by the plane wave expansion (PWE) method. Narrow transmission bandwidth of ∼10 nm with quality factor and confinement factor of 97.5% and 92% is achieved respectively, confirming strong confinement of the propagating mode at 633 nm and the losses calculated in decible per micrometer (dB/μm) for the waveguide is found to be .75 dB/μm for straight waveguide. Further, Y-splitter designed from the basis equally bifurcate power and the outputs received at the two ends are in phase yielding a viable 50-50 power splitter. Bend design routing light in nano-dimensions is also implemented successfully, offering components for high density plasmonic circuitry.