Abstract
We determine and analyze the properties of regenerated surface plasmon polaritons (R-SPPs) in an asymmetric waveguide structure [T.-W. Lee and S. K. Gray, Appl. Phys. Lett. 86, 141105 (2005)]. Both finite-difference time-domain (FDTD) calculations and frequency-domain modal analysis are employed. The FDTD results, which explicitly include excitation via attenuated total reflection, show an oscillatory dependence of the R-SPP propagation length as a function of core layer thickness , with maxima corresponding to 30-fold propagation enhancements. For fixed incident light wavelength and angle, a variety of thicknesses can therefore be used to excite very long propagating SPPs. Modal analysis shows that the oscillations are due to tuning through the opening of new transverse magnetic waveguide modes. In addition to increased propagation lengths, surface confinement is not significantly deteriorated and large intensity enhancements in the propagation region can also be achieved.
- Received 27 November 2007
DOI:https://doi.org/10.1103/PhysRevB.77.125407
©2008 American Physical Society